S12-380 instability?

lutorm · Post by **lutorm** » Thu Nov 23, 2006 12:24 pm

How about this: I have a Seasonic S12-380 powering a system with a DFI Infinity 975x/g mobo, an E6400 and a power-sucking ATI X1900XT video card, plus odds and ends. This system has a DC power draw at full cpu and video usage of about 185W, so this should be plenty margin for this PSU.

However, I was experiencing semi-regular crashes when playing games, only when using the onboard sound. I thought it had something to do with the drivers of the onboard sound chips, but when I posted on the DFI forum to ask about this, the answer was "You are running a PSU which is way, way below minimum requirements, which are 480W. That's what's causing the crashes." (When I told them that my system only uses 200W, how can I possibly need a 480W PSU, they proceeded with ad hominem attacks... But that's beside the point.)

The point is: I decided to try running with an Enermax 495W PSU I happened to have access to. The crashes appear to have gone away!

I also measured the 12V line voltage and the S12-380 sagged 0.16V while the Enermax 0.07V, so different but still way less than the 5% spec.

I'm interested in hearing your thoughts on this. I fully agree that the S12-380 would appear to have adequate capability for the ~200W power draw of the system, but apparently it's not doing something right since the system would reliably crash with the 380W but does not appear to do so with the 495W PSU.

jaganath · Post by **jaganath** » Thu Nov 23, 2006 12:43 pm

I'm interested in hearing your thoughts on this. I fully agree that the S12-380 would appear to have adequate capability for the ~200W power draw of the system, but apparently it's not doing something right since the system would reliably crash with the 380W but does not appear to do so with the 495W PSU.

Maybe something to do with the 12V rail? According to spec sheet S12-380 only has (10+15A), whereas Enermax 495 has 32A.

Post by **MikeC** » Thu Nov 23, 2006 12:47 pm

lutorm wrote:How about this: I have a Seasonic S12-380 powering a system with a DFI Infinity 975x/g mobo, an E6400 and a power-sucking ATI X1900XT video card, plus odds and ends. This system has a DC power draw at full cpu and video usage of about 185W, so this should be plenty margin for this PSU.

The point is: I decided to try running with an Enermax 495W PSU I happened to have access to. The crashes appear to have gone away! I also measured the 12V line voltage and the S12-380 sagged 0.16V while the Enermax 0.07V, so different but still way less than the 5% spec.

You say it should have a DC power draw of 185W... I'd say it's time to measure it and find out how much power is pulled from AC during game peaks. One thing we don't always know about is short term peaks imposed by games, vidcards and CPUs (we're talking about well under 1s), what impact these peaks have on PSU performance and on system stability.

I guess you could also try the same games w/ the same vidcard & CPU -- but all the odds and ends unpowered -- and see if the crashes still occur.

lutorm · Post by **lutorm** » Thu Nov 23, 2006 1:11 pm

MikeC wrote:You say it should have a DC power draw of 185W... I'd say it's time to measure it and find out how much power is pulled from AC during game peaks. One thing we don't always know about is short term peaks imposed by games, vidcards and CPUs (we're talking about well under 1s), what impact these peaks have on PSU performance and on system stability.

I guess you could also try the same games w/ the same vidcard & CPU -- but all the odds and ends unpowered -- and see if the crashes still occur.

No, I said the system draws 185W (this is based on AC power draw from the killawatt and 0.8 efficiency). I suspect the short-term variations is the issue, I'm going to get an oscilloscope and measure the time-variability of the 12V line, maybe that will show something.

And about the 12V capacity, it's true that it's only 25A total for the S12-380, but even 25Ax12V is 300W if all the load was 12V. In fact, I tried overclocking and got the AC power draw up to 300W. The system was still stable as long as I didn't use the onboard sound. This baffles me, you'd think that if the PSU is close to the limit, an extra 80W should have meant much higher instability, but it didn't...

jaganath · Post by **jaganath** » Thu Nov 23, 2006 2:00 pm

The system was still stable as long as I didn't use the onboard sound.

so don't use the onboard sound then.

about the 12V capacity, it's true that it's only 25A total for the S12-380

I thought you can't simply add the two 12V rails to get the combined power? For example the Enermax495 supposedly has 22A per 12V rail, but the combined 12V is only 32A.

Post by **MikeC** » Thu Nov 23, 2006 2:24 pm

jaganath wrote:
The system was still stable as long as I didn't use the onboard sound.
so don't use the onboard sound then.

Good point -- I missed that.

about the 12V capacity, it's true that it's only 25A total for the S12-380

I thought you can't simply add the two 12V rails to get the combined power? For example the Enermax495 supposedly has 22A per 12V rail, but the combined 12V is only 32A.[/quote]
This is generally true, but according to the specs on the S12-380 box (that I just looked at) the combined 12V power is 300W -- 25A.

In any case, it does seem like the problem is an interaction between the audio card/ driver and the Seasonic, not 12V power overload.

lutorm · Post by **lutorm** » Thu Nov 23, 2006 7:33 pm

jaganath wrote:
The system was still stable as long as I didn't use the onboard sound.
so don't use the onboard sound then.

That's what I've been doing, but a) if it's crashing when using that maybe it has other, less obvious, effects, and b) the onboard is 7.1 hidef which sounds fun.

Post by **NeilBlanchard** » Fri Nov 24, 2006 3:52 am

Hello,

Have you tried the latest sound driver? Because it certainly sounds like it is related to the sound, and not the power supply, per se. Maybe the motherboard's power section can't handle things when the sound is used? Or, there is a bug in the sound hardware/software?

andyb · Post by **andyb** » Fri Nov 24, 2006 7:07 am

Are you using a native PCI-E connector on the PSU, or are you using 2x Molex connectors to a PCI-E power adaptor cable.??? If you are using the adaptor, its usually a good idea to plug each of the molex connectors from a different mower cable.

The other thing to try is a BIOS option that is enabled by defailt on most motherboards. "Spread Spectrum" has been knows to cause pretty random errors in the past, you could try turning that of and see what happens.

Andy

lutorm · Post by **lutorm** » Fri Nov 24, 2006 11:59 am

My bad, the system still crashes with the 495W PSU... I don't know why it didn't initially, but it repeatably does now. Same as with the 380, crashes with OB sound, not with SB.

And yeah, I have the latest realtek drivers. Might try updating the bios but the changelog doesn't say anything was changed regarding the chips, only CPU support...

UK-Bob · Post by **UK-Bob** » Sat Dec 02, 2006 4:25 am

That 7.1 channel onboard sound will have a very high currant draw caused by the dynamics of the games that will be in short bursts. Lots of effect sounds contain low frequency that will cause massive peeks. Can you turn the gain on the board down independant from the volume ? Also it may be a just a conflict or hard ware incompatibility issue ?

I use an external soundcard thats only 2 channel but high quality and have the onboard multi channel dissabled but this is just my preferance.