i7 PC electrical noise leaking into audio recordings

skb_spcr · Post by **skb_spcr** » Wed Jun 24, 2009 7:28 pm

Hello,
I have a very challenging and annoying electrical noise problem that I believe is traceable to either my PC's power supply, motherboard, or processor. I hope some knowledgeable and helpful experts out there can help me figure out what to do next. Unfortunately, I don't have other power supplies, motherboards, or unlimited funds to drop and swap until the noise is gone. I need to carefully consider my best option(s) and go one step at a time. Here's the story:

Last month I built a new Intel i7 PC for music composition and audio recording. Everything was going great until I tried recording line-level analog audio from my hardware synthesizers. My i7 PC has an M-Audio Delta 1010 sound card (external A/D converter box) that was previously used in a Pentium III PC and made pristine recordings in that role. To my horror, analog recordings into this new i7 PC are accompanied by an obnoxious, wide-spectrum buzzing noise centered near 2.5kHz. This electrical noise is very obviously audible in .wav files recorded on this i7 PC.

Fortunately, I was able to reduce the noise by 8dB by disabling Speedstep in my bios as noted in a thread on the Corsair forum that I'm unable to post (ironically, those people cited acoustic noise whereas this solution helped reduce my electrical/audio noise). After this solution, however, the noise is still audible and needs further reduction/elimination for these recordings to be up to par.

A further solution is having my Delta 1010 A/D breakout box powered by a rackmount Furman power conditioner (RP-8). Supposedly these units have AC filtering circuitry within, and sure enough, placing this unit between the A/D box and the AC wall plug reduced the recorded electrical noise by another 2dB. But that's still not good enough - it's still audible, albeit at a low level.

So I have a few older PCs that have been reliable for pristine audio recordings for many years - one of which is a humble Toshiba 1.4GHz Pentium M laptop with an RME Hammerfall PCMCIA sound card (Multiface external A/D box). I repeated these recording tests using this old laptop with the following two conditions: new i7 powered OFF and i7 PC powered ON.

With the i7 PC merely powered ON (keep in mind, there are no connections between these 2 PCs.. and the synthesizer is being recorded directly into the Hammerfall A/D inputs.. so the only common link is that they both are drawing AC power..), the laptop records the SAME ELECTRICAL NOISE as originally found/noted in the i7 recordings (at a slightly lower level)!

With the i7 PC powered off, however, the laptop audio recordings were pristine as expected - no noise whatsover.

Therefore, this electrical noise is making its way from the i7 PC and into my other audio gear via my home's AC power path.

My question for the experts that know PCs, power supplies, motherboards, and AC: how should I go about eliminating this noise? What's my next best step?

(FWIW, Antec customer support recommended that I update my motherboard bios, which I promptly did, and found no improvement/change in my recording tests).

If the root cause is the i7 CPU, would switching to a different CPU be the best solution? For example, would I find solace in an Intel Core 2 Quad or AMD Phenom II CPU?

Or, is it the Gigabyte motherboard that needs to be swapped out? Isn't it the motherboard's job to filter and control the emissions of noisy chips? But isn't Gigabyte well-known as the best motherboard manufacturer out there? What could I try that would make a difference - Asus? Foxconn?

Or, is the PC power supply at fault? If I simply bought a much more expensive power supply, would I also buy better DC -> AC filtering? Is there a specific power supply model out there designed to handle the i7 and keep its noise within the PC?

Sorry for the long post, but there is a bit to consider. Your thoughts, comments, and questions would be most welcome. Here are my PC specs:

CPU: Intel i7 920 2.6 GHz
Motherboard: Gigabyte GA-EX58-UD4P
RAM: Super Talent 6GB DDR3
GPU: Sapphire Radeon HD4770
HD: Western Digital WD10000LSRTL
DVD: Sony AD-7240S-0B
PS: Antec Earthwatts 430W
Case: Antec Sonata Elite
Sound: M-Audio Delta 1010

Thanks,
Scott

lodestar · Post by **lodestar** » Wed Jun 24, 2009 9:24 pm

Unless someone else has experienced exactly the same problem and has a ready solution it looks like you have no choice but to try and isolate components that might be the source of the problem.

You can obviously unplug any case fans to eliminate those. There are PSU testers which would enable you to run the PSU without running the rest of the PC.

The only thing that strikes me about your system is that 430w seems a rather small power supply to run a Core i7 setup. If a PSU tester reveals nothing it might be worth swapping it out to something like a 650w model.

alleycat · Post by **alleycat** » Wed Jun 24, 2009 10:55 pm

I think 430W is perfectly adequate for that system. However, the power supply is the first thing I would try swapping, and it's certainly the easiest. Ideally it would be good if you could borrow one from somewhere. Try to get a completely different brand, even a cheap noname type. Alternatively, you could take the Earthwatts and put it in another system, and see if that causes the same problem. If it does, then you may have your answer. If it doesn't, then that doesn't necessarily rule out the PSU, as it could be the interaction of that particular PSU with the rest of the i7 systems's components. I'd be very interested to see the results (especially because I'm about to build a system with the same motherboard and processor!).

lodestar · Post by **lodestar** » Thu Jun 25, 2009 12:52 am

alleycat wrote:I think 430W is perfectly adequate for that system.

Intel don't. The Core i7 spec that they have issued says:

1. The PSU must have two (2) 12 V rails.
2. The PSU must be capable of a continuous current flow of 16 A at 12 V.
3. The PSU must be capable of a peak current flow of 19 A on the second 12 V rail.
4. The 5 V rails are of no importance, only the 12 V rails.

Intel recommends a minimum PSU power output of 450 W.

alleycat wrote:Try to get a completely different brand, even a cheap noname type.

No, no, no, that's a really bad idea. See
http://www.jonnyguru.com/modules.php?na ... 3&reid=123

Incidentally the Intel minimum PSU requirement of 450w takes no account of the graphics card which is another drain on the 12v PSU rail. Given an ATI 4770 I think 650w or so would be sensible.

I have built a Core i7 system, it has a GTX 285 and a Hiper Type R II 880w PSU.

deruberhanyok · Post by **deruberhanyok** » Thu Jun 25, 2009 4:47 am

I think 650W would be way too much for that system. 450W would be alright, 500W is about the max I'd think would be needed.

I'd definitely recommend trying a different power supply before anything else.

Also, welcome to SPCR!

alleycat · Post by **alleycat** » Thu Jun 25, 2009 5:00 am

Well I'm not going to derail this thread arguing with you about this, but I base my opinion on this PSU calculator, with everything operating at 100% load. To briefly test for the problem, almost any similarly rated PSU would be adequate. It's not as if he needs to run Prime95 for 24hrs

EDIT: fixed link

alm · Post by **alm** » Thu Jun 25, 2009 5:02 am

Try fiddling with the spread spectrum settings in the BIOS (higher settings give better electromagnetic interference protection), your problem definitely sounds like EMI.

lodestar wrote:Intel recommends a minimum PSU power output of 450 W.

Isn't this spec, like the recommended PSU for video cards, inflated to compensate for crappy cheap power supplies that claim 600W but can barely deliver 300W sustained? I haven't researched the i7 power usage very much, put I have a hard time believing that an i7 system's peak power draw will be above 430W without a power hungry GPU.

A Radeon 4770 appears to draw about 50-60W DC (estimated from AC power figures and an efficiency of 80%) when stressed, a Core i7 165W DC peak. I can't see how this plus the other hardware will even approach 450W. A quality 430W PSU should have no problems delivering 430W sustained, although it will be noisy. Unless the fan is really ramping up, I wouldn't worry about PSU capacity, although swapping it out for a different design may fix the problem.

I do agree with the warning against cheap power supplies.

skb_spcr · Post by **skb_spcr** » Thu Jun 25, 2009 9:04 am

Thanks so much for your replies. I have a few questions.

You can obviously unplug any case fans to eliminate those. There are PSU testers which would enable you to run the PSU without running the rest of the PC.

Thanks lodestar. Interesting suggestion, I've never heard of a PSU tester. Will these confirm noisy DC or AC signal(s)? I'll also try unplugging the case fans later today and repeat my recordings.

The only thing that strikes me about your system is that 430w seems a rather small power supply to run a Core i7 setup.

I was hesitant as well, but everything has functioned normally. What bothered my during the build was the Earthwatts PSU providing only a 2-pin CPU power connecter, whereas the Gigabyte motherboard manual recommended using a 4-pin. The extra 2 pins only appeared to be duplicates of PWR and GND. Perhaps this is where I went wrong?..

have built a Core i7 system, it has a GTX 285 and a Hiper Type R II 880w PSU.

Is this your PC? Do you do any audio recording with it?

However, the power supply is the first thing I would try swapping, and it's certainly the easiest.

Thanks alleycat. If you could recommend a power supply for my testing purposes, which would it be? Also, do we know if Antec manufactures their own power supplies, and if not, which other PSU manufacturers should I avoid in the interest of trying a completely different design?

Also, I poked around to see what PSU system builders are using. Endnoisepc appears to be using the Nexus 850W and Zalman 850W and 1000W. Are these solid choices?

I base my opinion on this PSU calculator

I also used that online Antec calculator before ordering any parts, and felt comfortable that this Earthwatts PSU would be sufficient - even if I added a few more HDs in the future.

Also, welcome to SPCR!

Thanks, deruberhanyok! Do you have an opinion on which power supply to try?

Try fiddling with the spread spectrum settings in the BIOS (higher settings give better electromagnetic interference protection), your problem definitely sounds like EMI.

Thanks, alm. Unfortunately, I was unable to locate any parameters in my GA-EX58-UD4P BIOS named spread spectrum. I did a search through the motherboard PDF manual and it's not documented under that name. Is there an acronym or other terminology that I should be looking for?

It sounds like you are suggesting the CPU itself is the source of emissions - which my Speedstep findings seem to confirm. If this is a case of excessive conducted emissions, does this mean my PC wouldn't pass EMI testing? Is it harmful to my health to use this new PC?

LodeHacker · Post by **LodeHacker** » Thu Jun 25, 2009 9:17 am

skb_spcr wrote:If this is a case of excessive conducted emissions, does this mean my PC wouldn't pass EMI testing? Is it harmful to my health to use this new PC?

Don't really know how it affects life, but here's content maybe of interest to you: http://www.kissmixer.com/emi/emi1.htm

K.Murx · Post by **K.Murx** » Thu Jun 25, 2009 10:15 am

Regarding the power supply:
I have a similar system (4770, Phenom X3, 8GB DD3, Gigabyte MB) and I draw ~140W from the wall during regular 2D use. Even with the more power-hungry i7 and speedstep disabled, there is no way his system exceeds the PSUs "comfort zone".

Back to the problem at hand:
As the power conditioner seems to help, I would suspect the AC power.
Just to double check, how about you reenable SpeedStep, and see how big a difference the power conditioner makes then? Make the recordings with your laptop, of course.

lodestar · Post by **lodestar** » Thu Jun 25, 2009 11:41 am

What bothered my during the build was the Earthwatts PSU providing only a 2-pin CPU power connecter, whereas the Gigabyte motherboard manual recommended using a 4-pin. The extra 2 pins only appeared to be duplicates of PWR and GND. Perhaps this is where I went wrong?..

Are you talking about the CPU power connector which is on the top left of the motherboard, above the CPU?

bonestonne · Post by **bonestonne** » Thu Jun 25, 2009 1:46 pm

i'd remove the blower fan over the PCI area, if you haven't already, and i'd check how you're running the Delta 1010 itself. the massive cable that goes from the breakout box into the card could simply be passing a source of electricity you're overlooking. i dropped my noise floor of recordings by routing cables directly away from my tower rather than next to it, and the noise floor dropped from around -64dB to close to -80dB.

if that's not it, you need to look at how you're running power in your case, and keep all cables away from it. the Delta 1010 doesn't need any extra power inputs, so the area around it should be relatively clear. The HD4770 might be causing some of your interference though, it might not be the biggest power eater, but it's got enough juice, and it's very close to your card. your computer will always give you varying degrees of noise floor though, i can't escape the one i have, but it's also good enough for me to live with.

I have an Antec SmartPower inside my low power HTPC, and while i'm not running any major applications on it, it doesn't give me issues anything like that.

alm · Post by **alm** » Thu Jun 25, 2009 2:24 pm

skb_spcr wrote:What bothered my during the build was the Earthwatts PSU providing only a 2-pin CPU power connecter, whereas the Gigabyte motherboard manual recommended using a 4-pin. The extra 2 pins only appeared to be duplicates of PWR and GND. Perhaps this is where I went wrong?

They are actually 4-pin and 8-pin connectors

. The extra four pins are indeed two extra 12V and two extra ground wires. More wires means more current capacity and less losses. The extra four wires are usually optional, although they may help stability if the CPU draws large amounts of current. Since you have this problem even if the i7 is idle, it doesn't sound like power draw is an issue.

skb_spcr wrote:Also, do we know if Antec manufactures their own power supplies, and if not, which other PSU manufacturers should I avoid in the interest of trying a completely different design?

Antec power supplies are made by (depending on the model) Seasonic, FSP and Delta (probably more). My guess is that the EarthWatts 430W is a Seasonic design, the review on SPCR should confirm that. Zalman designs its own power supplies, not sure about Nexus (my guess would be no). Many Corsair power supplies are also manufactured by Seasonic, some by CWT.

skb_spcr wrote:Thanks, alm. Unfortunately, I was unable to locate any parameters in my GA-EX58-UD4P BIOS named spread spectrum. I did a search through the motherboard PDF manual and it's not documented under that name. Is there an acronym or other terminology that I should be looking for?

It's usually called something like CPU spread spectrum or PCIE spread spectrum. Other terms are EMI and interference. I did a quick flip through the manual and I couldn't find anything related either. I would expect it to be in the M.I.T. section (obviously press ctrl+F1 first).

skb_spcr wrote:It sounds like you are suggesting the CPU itself is the source of emissions - which my Speedstep findings seem to confirm. If this is a case of excessive conducted emissions, does this mean my PC wouldn't pass EMI testing? Is it harmful to my health to use this new PC?

I doubt that any individual product would pass FCC tests if it would emit so much EM noise. I assume that it's caused by either a marginal component or an unlucky combination, somewhat like coil whine. I assume you ruled out EMI via radiation (does moving the A/D converter farther away change anything? removing a side panel from your i7 system?). Then the most likely component seems the PSU, since it's the closest to the power cord and supposed to filter the EM noise. I would try to RMA it, the filter circuit may be defective, so a different sample of the same could very well fix it. Speedstep has more of an impact on the VRM on the motherboard that provides power to the CPU, but will also cause the power draw to change often and load the PSU differently. In the end, PSU and motherboard seem possible, but PSU is IMO more likely and cheaper and easier to replace, especially for a Core i7.

Some other cheap things to try: strip it down as bare as possible. Remove 2 sticks of RAM, soundcard, HD, DVD (just let it sit in the BIOS), swap graphics card if you have another one that's PCI express. Then try to record from another system and see if you get any noise. It seems unlikely that any of these components is the culprit, but you don't have to buy any extra hardware to try this.

deruberhanyok · Post by **deruberhanyok** » Thu Jun 25, 2009 4:13 pm

In regards to the discussion about power use, Tech Report showed peak power consumption under 300W for an i7 965 with a Radeon 4870:

http://techreport.com/articles.x/15818/14

Their full test system setup is on page 4 of that article.

Thanks, deruberhanyok! Do you have an opinion on which power supply to try?

You're welcome!

I had an annoying noise issue of my own during an attempted upgrade last fall. It sounds similar to yours, although mine was clearly audible when the system was running.

In my testing of various things I used two different power supplies: a Corsair HX520W (two of these, one that I had and one a brand new replacement from Corsair) and a Silverstone ST50EF Plus. Both are exceptionally quiet and, once I decided to pair them with different hardware, didn't cause any noise that I could detect.

There are a few other brands I usually look at for parts - Antec, Fortron Source and Seasonic - but I don't have any experience with most of the current models from those companies.

As the numbers in the above linked article show, I really think anything over 500W would be unnecessary.

Also I've had another thought, something to try if you haven't already. Have you tried putting the PCI sound card part of your 1010 into both of the PCI slots on your motherboard? Perhaps it is picking up some interference from the motherboard.

I was hesitant as well, but everything has functioned normally. What bothered my during the build was the Earthwatts PSU providing only a 2-pin CPU power connecter, whereas the Gigabyte motherboard manual recommended using a 4-pin. The extra 2 pins only appeared to be duplicates of PWR and GND. Perhaps this is where I went wrong?

Curious. I can't say I've ever seen a 2-pin connector for that. The info on their website shows the 20+4 pin main connector and a 4-pin ATX 12V connector:

http://www.antec.com/Believe_it/connect ... odID=27430

Your supply is missing something there?

skb_spcr · Post by **skb_spcr** » Sun Jun 28, 2009 6:59 pm

Just wanted to write back and say thanks for all of your help and suggestions!

My initial nasty -70 dB Delta 1010 noise floor is now -84 to -86 dB. The Delta 1010 still has a dB or two of pitched AC noise riding on DC, whereas the RME (still on the Pentium M laptop...) has negligible noise on its DC around -89dB.

Another significant related finding is that analog output #1 of the Delta 1010 is MUCH more noisy (+15dB) than outputs 2-8. The DC power input happens to be right next to output #1...

Here is a summary of my initial efforts:

- relocated i7 AC cable from the same power strip as the Delta 1010 to an "upstream" path closer to the AC plug. result: at least 1 dB electrical noise reduction.

- added Furman power conditioner between Delta 1010 AD box DC adapter and AC outlet. result: 1-2 dB electrical noise reduction.

- disabled C1E and E1ST ("speedstep") parameters in the Gigabyte EX58-UD4P bios. result: 6-7 dB electrical noise reduction.

and my follow up efforts:

- disabled Delta 1010 MIDI out driver in Sonar. result: 5-6 dB electrical noise reduction.

- disabled Sonar's recording metronome audio output. result: ~1 dB electrical noise reduction.

- swapped Antec Earthwatts 430 PSU for BFG GS-550. this effected the frequency components of the AC noise (i.e. normalized AC noise "sounds" somewhat different), but did not effect the electrical noise amplitude.

- physically routed the Delta 1010 parallel cable and AD converter box to a new isolated location in the room. also tried moving power, source analog, and data cables around while recording. no effect on electrical noise.

- strip down the PC down one component at a time. decided not to do this because the Delta 1010 AD converters are disabled prior to Windows XP loading the M-Audio drivers. therefore, any measurements of Delta 1010 performance with the PC in bios (or DOS) would be unrealistic and misleading.

- disconnect DC case fans. decided not to do this because this is an unrealistic and possibly unsafe operating condition.

In summary, it was primarily the combination of the Gigabyte bios "speedstep" settings and Delta 1010 MIDI output that made up the majority of the recorded electrical noise. Among my recording equipment, this electrical noise is unique to my new i7 PC and concerns me because I have to be careful about dynamics processing applied to audio recorded through its analog inputs.

Someone on Anandtech suggested that the Gigabyte EX58 i7 motherboards create an audible whining/buzzing noise. It is possible - although unproven - that the source of that problem also causes the electrical noise I experienced. Personally, I would suggest that anyone who needs professional quality audio recording to be careful when choosing a motherboard and consider the issues presented in this thread and elsewhere. Good luck.

Thanks,
Scott

croddie · Post by **croddie** » Mon Jun 29, 2009 3:01 am

skb_spcr wrote:Last month I built a new Intel i7 PC for music composition and audio recording.

It's more of a gaming system but should work fine for this if it's quiet.

analog recordings into this new i7 PC are accompanied by an obnoxious, wide-spectrum buzzing noise centered near 2.5kHz. This electrical noise is very obviously audible in .wav files recorded on this i7 PC.

Is there a way to ground the breakout box directly to the same ground that your audio equipment is using? My gut feeling is this might solve the problem. However it's strange that electrical interference over a digital connection should affect the output of the breakout box if it has a separate power supply. It could well be a flaw in the M-Audio hardware because it should be isolated from that.

danimal · Post by **danimal** » Mon Jun 29, 2009 5:07 pm

i'm with croddie, it could be a ground loop relevant to the analog section... i do video editing, and i'm not sure that there is a scenario whereby humm and buzz can be introduced into a fully digital editing workflow(??).

fwiw, is everything plugged into the same ac power outlet? because the room you are in could have seperate ac lines that are homed into the power box... do you know for sure if there are any other appliances plugged into those ac line(s)?

skb_spcr · Post by **skb_spcr** » Tue Jun 30, 2009 7:25 am

croddie wrote:It's more of a gaming system but should work fine for this if it's quiet.

The i7 makes for a beast of an audio/music workstation, and the Sonata Elite is very quiet in operation. As long as all of the composition is happening "inside the box", it's fine. The audio recording quality is acceptable for now.

But I'm disappointed in the noise coming out of this motherboard. Clearly, Gigabyte's priority is to implement all sorts of new hardware technology in their boards. I should have seen this as a red flag, but now I know better. They probably didn't notice or care that they neglected one of the basics (audio quality). 7.1 isn't enough.

http://www.gigabyte.com.tw/Products/Mot ... uctID=2986

It's little wonder pro recording studios are loyal to Mac Pros. There would be a public rebellion in audio/music land if a new Mac Pro had this sort of problem. I wonder if this may be one reason that Apple hasn't done an i7 Mac Pro yet.

Is there a way to ground the breakout box directly to the same ground that your audio equipment is using? My gut feeling is this might solve the problem. However it's strange that electrical interference over a digital connection should affect the output of the breakout box if it has a separate power supply. It could well be a flaw in the M-Audio hardware because it should be isolated from that.

There certainly is a flaw within the Delta 1010: activating the Delta's MIDI output increases pickup of AC noise. That's shocking because you expect audio and MIDI to be mutually exclusive. The noise I'm dealing with is not a simple 60Hz ground loop. There's something else going on that quite frankly should be investigated by Gigabyte's engineers, not me.

LodeHacker · Post by **LodeHacker** » Tue Jun 30, 2009 8:27 am

skb_spcr wrote:I wonder if this may be one reason that Apple hasn't done an i7 Mac Pro yet.

Who said that? http://www.engadget.com/2009/03/14/appl ... -hands-on/

Remember though, that a Mac computer is upgradeable only to a certain point, while the PC platform gives you the freedom to build any kind of system for any need. Having said this it also should be noted, that Mac is identical to current generation PC technology at the component level. Your real problem is most likely the motherboard or PSU, possible a combination of both. Get a quality motherboard intended for workstation usage and you might get rid of that electrical noise there.

I mean, it is NOT acceptable that you disable MIDI for example. It's core functionality of a high quality audio product from M-Audio. They are not at fault.

skb_spcr · Post by **skb_spcr** » Tue Jun 30, 2009 12:30 pm

Nice - somehow I completely missed that. I'm curious to know who is building the motherboard for that new Mac Pro!

As far as MIDI goes, I don't need the Delta MIDI out. I have a multiport Edirol USB MIDI hub for that.

LodeHacker · Post by **LodeHacker** » Tue Jun 30, 2009 1:28 pm

skb_spcr wrote:I'm curious to know who is building the motherboard for that new Mac Pro!

danimal · Post by **danimal** » Tue Jun 30, 2009 7:58 pm

skb_spcr wrote: But I'm disappointed in the noise coming out of this motherboard. Clearly, Gigabyte's priority is to implement all sorts of new hardware technology in their boards. I should have seen this as a red flag, but now I know better. They probably didn't notice or care that they neglected one of the basics (audio quality). 7.1 isn't enough.

http://www.gigabyte.com.tw/Products/Mot ... uctID=2986

???

i must be missing something, because i don't see anything on that page that could be responsible for this noise problem.

danimal · Post by **danimal** » Tue Jun 30, 2009 8:02 pm

LodeHacker wrote:
skb_spcr wrote:I'm curious to know who is building the motherboard for that new Mac Pro!

lol... actually, intel makes the pc motherboards for apple.

LodeHacker · Post by **LodeHacker** » Wed Jul 01, 2009 1:13 am

danimal wrote:
LodeHacker wrote:
skb_spcr wrote:I'm curious to know who is building the motherboard for that new Mac Pro!
lol... actually, intel makes the pc motherboards for apple.

That is true, but I wanted to have the fun, don't spoil it

croddie · Post by **croddie** » Wed Jul 01, 2009 6:56 am

skb_spcr wrote:But I'm disappointed in the noise coming out of this motherboard. Clearly, Gigabyte's priority is to implement all sorts of new hardware technology in their boards. I should have seen this as a red flag, but now I know better. They probably didn't notice or care that they neglected one of the basics (audio quality). 7.1 isn't enough.

That was Gigabyte's priority for this board because it's an enthusiast board which will have the highest performance/features without much regard for power consumption... so not an SPCR board really. The target audience doesn't care much about audio quality and it probably has similar audio quality to other onboard audio... which we're not discussing anyway.

It's little wonder pro recording studios are loyal to Mac Pros. There would be a public rebellion in audio/music land if a new Mac Pro had this sort of problem. I wonder if this may be one reason that Apple hasn't done an i7 Mac Pro yet.

Actually Pro Recording studios don't use M-Audio, it's more of a consumer-level brand for music lovers (fine for what it does of course). The problem seems to be with the M-Audio breakout box. And may be fixable. The motherboard may be exacerbating it but isn't the problem.
There is electrical noise in all computers but it won't affect a pro audio card if its is well designed. (Grounding problems may exist but are easily fixed.)

The noise I'm dealing with is not a simple 60Hz ground loop. There's something else going on that quite frankly should be investigated by Gigabyte's engineers, not me.

There is more than one type of grounding problem. It's been a while since I looked this stuff up. Does the box have a ground connector? If so connect it to the same ground as your other stuff and I think the problem will go away.

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