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 Post subject: Mount motherboard isolated from case?
PostPosted: Wed May 11, 2005 9:17 pm 
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Has anyone had any luck with mounting a motherboard in such a way
so as to avoid that it transmits vibrations to the case, using a technology similar to fan isolators, or using any other means?


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 Post subject:
PostPosted: Wed May 11, 2005 9:43 pm 
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The motherboard is supposed to be grounded to the chassis via the metal standoffs. They also help dissipate some heat.

Not too many motherboards transmit vibrations or noise. Some motherboards have high frequency coil whine which is very effectively transmitted through the air, and would not be diminished enough to matter if the motherboard was isolated from the chassis.


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 Post subject: Re: Mount motherboard isolated from case?
PostPosted: Wed May 11, 2005 9:45 pm 
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Aracu wrote:
Has anyone had any luck with mounting a motherboard in such a way
so as to avoid that it transmits vibrations to the case, using a technology similar to fan isolators, or using any other means?

On many motherboards, the only moving component is the fan on the CPU heat sink (NB HSF can be replaced). Several users have been successful in modifying the CNPS7000 so that there is no hard surface to hard surface contact between fan and motherboard. That would be a much easier mod than suspending the motherboard.


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 Post subject:
PostPosted: Thu May 12, 2005 7:23 am 
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I would think this would also require that your expansion cards not be secured to the case as well--as Lenny said, it's probably much easier to focus on decoupling the vibration sources from the motherboard/cards.

m0002a wrote:
The motherboard is supposed to be grounded to the chassis via the metal standoffs. They also help dissipate some heat.
Huh? How do a half-dozen brass (or sometimes plastic) standoffs transfer an appreciable amount of heat from the board?

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 Post subject:
PostPosted: Thu May 12, 2005 7:51 am 
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Shriek wrote:
m0002a wrote:
The motherboard is supposed to be grounded to the chassis via the metal standoffs. They also help dissipate some heat.
Huh? How do a half-dozen brass (or sometimes plastic) standoffs transfer an appreciable amount of heat from the board?


Next to nothing, if they are plastic then they wont do any good at all, and even if they were of copper and the backplate was of copper the effect would be neglidgable.

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 Post subject:
PostPosted: Thu May 12, 2005 8:54 am 
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I was also wondering about the motherboard standoffs myself. Besides the CPU HSF often people will also have a Northbridge fan like on NF boards, and a fan on their video card, which is indirectly connected to the motherboard.

For a place like SPCR whose members use a variety of silencing techniques, and who could want every last 1/10 or 1/100 of extra silencing and decoupling, I think this might be worth looking into.

Are motherboards really grounded through the standoffs as mentioned...? :? What about those people who build wood or acrylic cases then?

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 Post subject:
PostPosted: Thu May 12, 2005 10:18 am 
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I ran run many systems with the motherboard completely ungrounded for a long time, and as said in acryllic cases the mobo is ungrounded so it shouldnt matter.

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 Post subject:
PostPosted: Thu May 12, 2005 11:05 am 
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I didn't say that a motherboard is not grounded at all if not attached to the case. It is grounded to PSU. But it does provide additional grounding to the rest of the case. This is not absolutely required, but is desirable. At one time at least, some drives needed to grounded to a grounded case in order to even work (I had a bad experience trying to get a floppy drive to work that was connected via power and flat cable, but would not work unless grounded to the case via side installation screws).

I didn't say that the there is a lot of heat dissipation through the standoffs, but there is some.

If you isolate your motherboard, it will not provide an additional 1/10 or 1/100 of extra silencing, unless you have fundamental problems elsewhere. On both counts, the amount of additional grounding and the additional cooling is more than any additional vibration/noise that could be transmitted through the standoffs, unless the existing fans on the motherboard are poor and/or very poorly mounted (in which case they should be replaced or remounted).

But is seems to me that there is a double standard being applied here. It is OK to decrease vibration by 1/100, but it is somehow irrelevant to increase grounding or heat disposition by that small amount?


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 Post subject:
PostPosted: Thu May 12, 2005 11:34 am 
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BrianE wrote:
Besides the CPU HSF often people will also have a Northbridge fan like on NF boards, and a fan on their video card, which is indirectly connected to the motherboard.

For a place like SPCR whose members use a variety of silencing techniques, and who could want every last 1/10 or 1/100 of extra silencing and decoupling, I think this might be worth looking into.



I think it would be much more effective to decouple or remove those fans.

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 Post subject:
PostPosted: Thu May 12, 2005 1:00 pm 
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I think that the HS fan can add an appreciable amount of vibration to the motherboard....not too many people even around here have decoupled that particular fan...woudn't be like unmounting a hard drive, but could make a measurable difference.


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 Post subject:
PostPosted: Thu May 12, 2005 1:15 pm 
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Green Shoes wrote:
I think that the HS fan can add an appreciable amount of vibration to the motherboard....not too many people even around here have decoupled that particular fan...woudn't be like unmounting a hard drive, but could make a measurable difference.

Are you talking about the CPU HS fan? The ThemalrightXP-120 and XP-90 come with an isolation strip (silicone or rubber, etc) that isolates it to a large degree. The spring clip is flexible, so it doesn't transmit much vibration.

On other CPU HSF's, even those with included fans, I have always removed the fan and installed some silicone caulk.


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 Post subject:
PostPosted: Thu May 12, 2005 1:31 pm 
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I was just wondering if this was "okay" to do or not :( .... I mean you could replace the standoffs pretty easily while putting the computer together using some chunks of rubber tubing or stiff foam blocks or something.

People are always doing all sorts of extreme, tiny little modifications (whether it be to cars or computers...) and whether they work or really offer much benefit or not is sometimes a secondary consideration to actually just doing it. This kind of thing seems to fall under this category... but as long as there's no penalty involved I'd probably attempt it anyway. :P

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 Post subject:
PostPosted: Thu May 12, 2005 3:04 pm 
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BrianE wrote:
I was just wondering if this was "okay" to do or not :( .... I mean you could replace the standoffs pretty easily while putting the computer together using some chunks of rubber tubing or stiff foam blocks or something.

People are always doing all sorts of extreme, tiny little modifications (whether it be to cars or computers...) and whether they work or really offer much benefit or not is sometimes a secondary consideration to actually just doing it. This kind of thing seems to fall under this category... but as long as there's no penalty involved I'd probably attempt it anyway. :P

Your PC will not quit working, if that is what you mean. But there are some advantages IMO to attaching it with metal screws. My PSU is not grounded very well to my case because I mount it with silicone, so I would prefer to make sure the case is grounded to the MB.

Sure there are lots of people who mod things for no good reason. There are also tens of thousands of people who commit suicide each year.

Granted, it does seem that some people only build a PC to post on this forum (and maybe run folding), but for most people they build a quiet PC to be used for other things besides trying to figure out how to build a quieter PC.

If you really want to do it, I would go to the hardware store and get some plastic (nylon) standoffs, and screws and nuts that fits through the center of the standoffs. If you don't want to use nylon screws and nuts, you can use nylon or rubber washers on the metal screws with nylon standoffs.

While at the hardware store, maybe you should get a smaller hammer, so you won't be running around looking for so many nails to hit it with.


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 Post subject:
PostPosted: Thu May 12, 2005 3:37 pm 
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i think that's a little harsh. although i agree that eliminating and decoupling fans should be a first step i see no reason to dismiss this idea so quickly. my experience of fan decoupling so far has been that vibration is reduced but not eliminated completely therefore i believe that there are certain situations, maybe within aluminium cases, where this idea may provide a tangible benefit.
i find the heat transfer argument a little difficult to swallow, i'v never noticed these points warming up. as for the grounding argument, this is no longer the case with modern hardware. if u inspect ur motherboard u will find that the points where it is fastened to the posts are isolated not grounded. many of my test rigs over the years have been laid on foam just like some of SPCR's test rigs, i'v never encountered any problems.
my main concern for using this idea within a standard case would be the difficulty of decoupling the ports or i/o gasket and the add-in cards, but maybe i haven't thought about it enough yet...


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 Post subject:
PostPosted: Thu May 12, 2005 3:48 pm 
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merlyn wrote:
i think that's a little harsh. although i agree that eliminating and decoupling fans should be a first step i see no reason to dismiss this idea so quickly.

I am not dismissing the idea so quickly if there are some identifiable benefits. What I am dismissing is the idea that it is OK just because:

"People are always doing all sorts of extreme, tiny little modifications (whether it be to cars or computers...) and whether they work or really offer much benefit or not is sometimes a secondary consideration to actually just doing it."

As others have noted, your video card (and other cards) is securely mounts attaches the MB to the case, so if there is a problem with a fan, it should be isolated at the source where it comes into contact with the HS.

I am big on isolation. I use 100% silicone caulk very liberally when I build I system.


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 Post subject:
PostPosted: Thu May 12, 2005 4:34 pm 
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m0002a -

Let him do his mod in peace. Wanting to use rubber mounts for isolation is no crazier than thinking you need to keep the metal ones for heat dissipation reasons. IMO anyway.

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 Post subject:
PostPosted: Thu May 12, 2005 4:55 pm 
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wsc wrote:
m0002a -

Let him do his mod in peace. Wanting to use rubber mounts for isolation is no crazier than thinking you need to keep the metal ones for heat dissipation reasons. IMO anyway.

I didn't say that one "needs to" keep the metal standoffs for heat dissipation. I said it is a benefit, admittedly slight. Again, here is the double standard at work where small or non-existent benefit of isolating the MB is compared to a small benefit of MB heat dissipation, and somehow isolating the MB always wins. Why is that?

There is also the issue of grounding, but I admit there are different, but strongly held opinions on this, especially with newer computers. Personally, I would ask the MB manufacturer.

Insofar as “letting” him do it, I assume the reason he was posting was to ask people for opinions. If he just wants to do, for no reason other than to do it, even if there is no benefit, then it is hard to come up with any rational argument against that (just like it hard to argue against a $1,000 IEC power cord since there is harm in it). But I took him at his word when he asked for opinions.

My opinion is that isolation is important, but that one should isolate at the source, which in this situation means isolating the fan or other moving part, rather than isolating the entire MB.


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 Post subject:
PostPosted: Thu May 12, 2005 5:36 pm 
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Unless you can isolate it strongly, I wouldn't like to do it with a heavy heatsink installed. And you still have the problem with your video card attached to the case, so you'll never achieve isolation unless you cut the bars between expansion cards and plug in through the case - do you really want to go to all that effort?

(FWIW I never liked the plastic mounts much, though the fact that they can and have been used shows that grounding can't be an issue.)

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 Post subject:
PostPosted: Thu May 12, 2005 8:29 pm 
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O.K., it looks like 1. we are not sure if new motherboards as a general
rule need to be connected to the metal mounts of the case. However, 2. if the only cause of audible vibration from a motherboard is from cpu or
other fans attached to it, it would make sense to isolate those fans rather than the motherboard if possible. This could be applied to the graphics card also, to isolate it's fan (if it has one) or replace it's fan with heatsinks, rather than try to isolate the whole card.
If there is still vibration left after isolating all the fans for some
unforseen reason, then maybe try isolating the motherboard, because the case can amplify the sound a substantial amount, though making sure that the mobo is grounded and not heating up too much.


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 Post subject:
PostPosted: Fri May 13, 2005 1:17 pm 
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m0002a wrote:
I didn't say that one "needs to" keep the metal standoffs for heat dissipation. I said it is a benefit, admittedly slight. Again, here is the double standard at work where small or non-existent benefit of isolating the MB is compared to a small benefit of MB heat dissipation, and somehow isolating the MB always wins. Why is that?

I'm not so much arguing the intricacies of your idea vs his, as I am trying to say that I felt it was rather rude to make statements such as the one regarding buying a smaller hammer, etc. If I was unclear about that, I apologize, but this is SPCR and the M.O. has usually been to avoid making comments and posts that can be interpreted in a rude or negative light. Maybe I totally misread your post though, I dunno.

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 Post subject:
PostPosted: Fri May 13, 2005 1:35 pm 
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wsc wrote:
I'm not so much arguing the intricacies of your idea vs his, as I am trying to say that I felt it was rather rude to make statements such as the one regarding buying a smaller hammer, etc. If I was unclear about that, I apologize, but this is SPCR and the M.O. has usually been to avoid making comments and posts that can be interpreted in a rude or negative light. Maybe I totally misread your post though, I dunno.

There is nothing to apologize for. I just don’t want anyone to thing that using metal MB risers makes any significant difference in heat dissipation. Actually, I read that somewhere and don’t know myself how important it is, but I suspect the benefit is very small.

I did make some rather sarcastic statements about the reality of quiet computing vs. tinkering with a computer as a hobby. There is another thread called "Audiophilia: hobby or disease" that is equally sarcastic about audiophiles who think they can hear the difference between a $100 cable and a $2,000 cable in a high end audio system. There have been many posts on this forum (including from me) who ridicule the kind of PSU “power prestige” (beyond needed requirements) that you see on other PC forums.

There is no doubt that Quiet Computing can be obsession beyond what is reasonable (I can personally attest to this), and there is no doubt that many people who like to tinker do have a hammer looking for a nail (I sometimes plead guilty to this also). That is the nature of tinkering (or a hobby). There is nothing wrong with that if it is understood as a hobby and not something that will produce any meaningful results. If it is rude to point that out, then I plead guilty. Married guys get these things pointed out to them on a daily basis.


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 Post subject:
PostPosted: Fri May 13, 2005 9:46 pm 
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You made some insightful points and didn't need to express them in a
negative way to get them across. It's funny how passionate we get
talking about computer parts. The complexity and rapid change of the
technology is unnerving. Our belief systems about it are constantly
being challanged. Technology which is hard or impossible to understand
in all it's complexity becomes part of our daily lives, and is seductive
in the power it offers. I understand the obsession for a silent pc since
I use it as the central unit of a recording studio. As the computers
become more powerfull and generate more heat, it takes more
analytical effort to modify the traditional design to make them silent.

I'm wondering if there is an easy solution to mounting the motherboard so
that it doesn't transmit vibrations, without having to remove those
metal pegs, and still have everything fit together the same so that the
external connections still match up.


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 Post subject:
PostPosted: Fri May 13, 2005 10:22 pm 
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Aracu wrote:
You made some insightful points and didn't need to express them in a negative way to get them across.

I didn't express it any more negatively than the what others on this site say about the over-clocker forums and audiophiles on other sites (or even the audiophiles on this site). Likewise, the people on other sites thing we a sissies for using low speed fans, reasonable wattage PSU's, and worrying about quiet computers, etc. Some of what I said was tongue-in-check, but of course, you have to have a sense of humor and some humility to appreciate it.

Just curious though, when you run your PC, can you actually feel any vibration on your motherboard? I am assuming that some reasonable effort has already been made to isolate the fans. If there is any vibration (my MB does not vibrate at all), do you have any reason to believe that it translates into noise?


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