TonyM16 wrote:That Silverstone Zeus 850watt psu is more than capable of running a Qx6700 and 8800gtx sli sytem thats also overclocked. first of all the psu is rated at 50c and has a peak output of 1050watt. Second the worlds greatest becner actually uses this very psu for his record breaking benchmarks. Yes thats right I am talking about Kingpin with his 4.5ghz QX6700, twin 900mhz core 8800gtx sli and 24k 3d mark 06. He said his 12v stayed at 12.03v throughout all his tests. He is not the only one. Johnny Guru and xtreme systems.org all place the Zeus at the very top end of all psu's. They have it in a a very high place way beyond most other psu's.
So I think the problem is something else and not the psu. I actually laughed when I heard that Nvidia themselves told you that the psu is the problem when that psu and the 750watt version ( a strong testament to the the psu efficiency) are both 8800gtx sli fully certified.
So I have to ask how did you load the psu up? I believe you loaded it up wrong. To load up that psu correctley you want the single 12v rail with the two pcieX cable ie 12v4 and pciX1+2 split to each 8800gtx. This way the shared 18amps gets shared to each gpu. You now have 9 amps going to each gpu. To finish just plu in the remaining cables. You will now end up with 36amps to each gpu. If you do it the other way where you have both 12v4 on one gpu , then one gpu will have 18amps only where as the other will have 36amps. Thats not good for overclocking.
I suggest trying the psu again like I described. That psu is alot better than anything else on the market, and should have no problems with a Kentsfield and 8800gtx sli.
Thanks a lot for the feedback and maybe I just happened to get two bad power supplies from Silverstone then. I've personally met and talked with John over at Jonny Guru and Fugger at Xtreme Systems and we all know a ton on power supplies and are generally on the same page when it comes to quality and performance. I did have the PSU wired as you described and it still dipped below 12V... For what it's worth this article was written before the P23 BIOS was even started and much of the instability issues seen go back to BIOS issues... It's a great PSU, but when you take a 4GHz Kentsfield processor, a water cooler, 2 8800GTX GPU's, a PhysX card, 4GB of memory, 4 500GB hard drives, a couple optical drives and load everything... meaning all four CPU cores at full load, the video cards running full blast, burning a DVD and listening to an audio CD while defragging the hard drives it dips and others don't... How do I know? Because I've done it a number of times!
Wow. Is that what you were doing with that psu. Hmm. I suppose in that situation it could be overstretched as it has to share its 18 amp 12v rails with the gpus and cpu along with the other stuff when you load it like how you done which is unlike the 1000watt psu's (unless it's a single rail one) which seem to keep gpu and cpu completely separate .
Also as people who used it for their 22k+ 3d mark 06 scores probably don't have more than one HD and cd drive and they certainly won't be multitasking as they want the highest score possible, from what I have seen most of those guys don't even game very often . Perhaps if they did try and game with their mammoth OC the psu would fail.
It's a difficult one. there are not that many psu's out there for people like us that we can safely say is THE ONE to get. The new PCP+C 1kw (is that the sr version?) you have is great and is probably the best psu in the world , but is just too costly and loud for the average 8800gtx sli user who just wants to game.
Ofcourse like you said it could have been a bios thing.
PS. Forgive me if I came across like I thought you didn't know what you were doing. Thats isn't the case. In fact I really enjoyed the article, and read it cover to cover before venturing off on my own adventure with the 8800gtx sli. I nearly bought the Silverstone Zeus 850watt , which is why I was so concerned about that aspect of the article. You may laugh but I bought a Tagan 1100watt instead. I know it isn't the best but it seems to do the job , and it seems very stable at it's 12v rail, I never saw it dip in to 11 at all. I was tempted to get the Zeus anyway later on as I didn't like how the Olympia 1000 turned out (very high ripple), but it looks like it won't be worth it if it can't hold the 12v rail with all that stuff (not that i would need it to, but the whole point was to have a future proof and reliable psu, and loading up like that should give us an idea as to how it will perform with next next gen gpus).