Asus M3A78-EMH HDMI (AMD 780G) power consumption

[GnatGoSplat]

I got bored and got the bug to switch motherboards in my HTPC. I read great things about the 780G and being fascinated by the latest low power consumption chipsets with powerful IGPs, I decided to replace my aging setup.

Old motherboard was an Asrock ALiveNF6G-DVI with Geforce 6100 chipset, AMD Sempron 3200+ 62W, and Geforce 8400GS 256MB passive video card.

I replaced those parts with an Asus M3A78-EMH HDMI 780G chipset and AMD Athlon LE-1600 45W.

My tuner cards, RAM, PSU, drives, peripherals, OS, everything else remained the same.

There was ZERO improvement in power consumption, according to my Kill-A-Watt. They both idled around 85W with CnQ active and under HDTV load used around 110W (apparently my tuner cards use 30W or so). In fact, the Asus board seems like it may consume a couple watts more power than the old Asrock setup. What I don't understand is, how can a setup with IGP and lower TDP CPU use as much power as a setup with discrete graphics?

When testing with FRAPS, I seem to get more stable framerates in Vista Media Center with the old setup, the 8400GS was more powerful than the 780G. Since there is no benefit in power consumption, I'm wondering if I ought to just switch back. Would I get better picture quality with the 8400GS or 780G?

[nutball]

They both idled around 85W with CnQ active and under HDTV load used around 110W (apparently my tuner cards use 30W or so).

How many tuner cards and drives have you got in that thing?!

[NX3]

My Gigabyte 780g idles at 42 so I guess your tuner cards account for the rest. It relative, my old 690v setup (everyting the same bar mobo) idles at 42 also. The key point if I have a IGP that can do DX10 and it it low power usage for the spec. How big is the heatsink on the 8400GS ? The 780g chipset heatsink is much smaller than a video card.

If your happy with your 6100/8400 setup and uses less power and thats a priority I'd go back. If you want DX10 features and HD playback from the IGP then stick with the 780G. The UVD is good at playback, the 8400 is probably using more power when doing HD playback.

[GnatGoSplat]

I only have 2 tuner cards and 2 drives:
- Vbox Cat's Eye 164e dual ATSC tuner
- Twinhan 1025 DVB-S digital satellite tuner
- Pioneer DVR-106 DVD slot drive
- Seagate 250GB ATA drive

I think PSU is a Seasonic but I didn't look last time I had it apart.

My test setup with the 780G mobo hooked up to a cheap junky 400W POWMAX PSU, Seagate 160GB SATA and Liteon DVD-ROM drive only used about 75W under load playing a 1080i video in Vista Media Center x64 and idled around 55W so it has to be one of the tuners guzzling a lot of power. The Vbox card is probably the power guzzler, that thing has heatsinks on all ICs on one side and they ALL get flaming hot. There are ICs on the other side that don't have heatsinks, but they also get very hot.

I'm mainly just surprised the 780G is almost a tie in power consumption to a 6100/8400GS. The 8400GS must be a lot more efficient than I gave it credit. I expected 10-20W less power consumption with the IGP.

[NX3]

The power supply can have an effect overall if its not very efficent and maybe the seasonic is. I switched my setup to a seasonic SII which is 80+ efficient a while back and that bought down my wattage.

[GnatGoSplat]

True, although I used the same PSU when I put both setups into my HTPC case so 780G seems to use the same power as the 6100/8400GS.

The 780G is very impressive for an IGP and is working fine, but I've scoured Google for reviews and it looks like the 780G is scoring 45-55 on HD HQV with a non-Phenom CPU while the 8400GS scores 80-95. Granted, that test is highly subjective but the numbers are fairly close between different reviews. I will probably switch back since I like knowing I've chosen the setup with the better picture quality.

I did see a 780G with Phenom 9600 (I think) can score an 80, but that's a $215 95W CPU so doesn't make sense for me economically since I don't use the HTPC for anything more than an HDTV DVR.

[Erssa]

True, although I used the same PSU when I put both setups into my HTPC case so 780G seems to use the same power as the 6100/8400GS.

Well 780G performs as well as 8400GS in gaming. I'm not really surprised it uses a bit more power then previous IGPs, when it is so powerful.

The 780G is very impressive for an IGP and is working fine, but I've scoured Google for reviews and it looks like the 780G is scoring 45-55 on HD HQV with a non-Phenom CPU while the 8400GS scores 80-95. Granted, that test is highly subjective but the numbers are fairly close between different reviews. I will probably switch back since I like knowing I've chosen the setup with the better picture quality.

In their 780G review anandtech made some pretty interesting comment on the subjectivity.

"Overall, we do not put much faith into this test currently as our eight person panel seemed to have a different opinion on just about every score. In fact, only three of our esteemed colleagues were in agreement with each other on test scores for each board and those were different (higher) than our published results."

But I guess you have already read that one, since you knew about the 80 points with Phenom...

Btw where have you seen 8400GS score ~90? For example in this test8400GS scored rather poorly, only 45. Granted, that test is pretty old, so it's possible nvidia has improved their drivers, but still I find it a bit hard to believe 8400GS would outperform 780G. Too bad there isn't a single benchmark out there, where you could see a direct comparison.

I think this article might be worth checking out as MissingRemote is a good HTPC forum. They use 780Gs integrated graphics in both the budget build with 4850e and the mainstream build with Phenom.

"A second very attractive option should be appearing this summer in the form of a low power Phenom quad-core CPU named the Phenom 9150e, it has a 65 watt thermal design, and unlocks the full potential of the AMD 780G's video abilities. Since the Phenom series uses the new Hyper Transport 3.0 link found on AM2+ motherboards it provides more bandwidth for the integrated video and CPU to communicate, this boosts not only 3D performance but also enables the 780G to post-process 1080i video properly."

Unless of course your 780G motherboard is A12 rev, because of thislittle bug. I see no reason why a Phenom 8450 wouldn't be a decent choice as well. It almost feels like tri-cores are made for HTPCs, because frankly they don't make much sense elsewhere.

Well anyway, I'm pretty sure you have already made up your mind about returning to 8400GS, but I decided to post this stuff, because it might be useful for some other people...

[GnatGoSplat]

Yeah, it's definitely a good IGP and runs surprisingly cool, although this may just be the case with the Asus board since Asus uses a fairly large heatsink.

The review that gives the 8400GS a 95 score is actually older than the one you linked to, it's a Chinese review here.
Here is a Korean review that gives it a score of 80.

On the other hand, here is another Korean review that gives the 8400GS a score of zero on everything. It seems HD HQV might just be too subjective to mean much of anything. I would buy HD HQV and compare for myself, but I don't have an HD-DVD-ROM drive or BD-ROM drive in my machine and at current prices, won't have one for some time.

Phenoms seem to really improve the 780G's video abilities, but the problem is the Phenoms, even the 8450, are a lot more expensive than just using a less expensive CPU and buying a video card like the 8600GT which seems to consistently score 90+ on HD HQV in almost every review.

I'm still not positive I'm switching back... my old setup had a really annoying problem where it wouldn't always wake from S3 suspend despite a clean install and it had the same problem in both XP and Vista. The M3A78 doesn't seem to have that problem and so far, has been extremely stable and bug-free.