*updated* twin 7900gt @ 580Mhz SLI, PSU, Case cooling help

[echoplex]

Hi guys n gals. I think I've got a power problem here lol. Linky to the specs of the PSU I own (specs for my PC are at the end of this post)

http://www.viperlair.com/reviews/cases/antec/psu/neo480/

I'm only getting the blue screen of death in Battlefield 2 with SLI enabled. Most of the time it just locks up and I can't even Alt-Tab to desktop. As soon as I shut SLI off I can run BF2 all day without any hiccups. Not enough juice to power my system with a 480W PSU and twin superclocked 7900GTs, right?

Check this out though...I play oblivion a lot at 1920x1200 with everything almost at max settings and I don't get the crashes. Oblivion does have a little stutter here and there but I always thought this was normal.

My questions to you are: why do I crash in BF2 and not in Oblivion? If the power supply can't handle the load, shouldn't it crash in all 3D intensive games? I thought I read somewhere in either the motherboard or GPU manuals that my PSU was barely making it with SLI enabled. I figured because it was a quality PSU and that the CPU I have (AM2 3800+ orleans) doesn't require much power, that I would be safe. The 12V rails on the Neopower 480 have a combined current capacity of 33A right? I read on the NVidia SLI forums that SLI required only 22A. I didn't think the other components in my system would require much current from the 12V rails...

What do you guys think? Another issue I have is that if I need another PSU I'll grab an 850W PSU just incase I want to go for quad SLI in the future...except the Silverstone one I was looking at was extremely long and I'm worried it won't fit in my case without modifications. Any reccomendations on a smaller, high wattage PSU for my case?

Thanks agagin folks.

Specs:
AMD 3800+ AM2
Mushkin DDR2 800
Raptor 74G
Gigabyte NVidia 590SLI motherboard
2x EVGA 7900GT KO Superclocked @ 580Mhz core
Antec Neopwer 480W PSU
Plextor SATA optical drive
Logitech G15 Keyboard + Razer mouse
Dell 24 incher
Lian Li 101-a case

 

[Cheese]

Dual-7900 GT's require two power supply units due to a nvidia driver bug. So you will have to run one on PSU A and one on PSU B.

newegg has a good deal on dual-PSU capable cases you should check out.

 

[Gary_Busey]

Dual-7900 GT's require two power supply units due to a nvidia driver bug. So you will have to run one on PSU A and one on PSU B.

newegg has a good deal on dual-PSU capable cases you should check out.

That's absolutely not true. Where'd you come up with that?

 

[prozac26]

Dual-7900 GT's require two power supply units due to a nvidia driver bug. So you will have to run one on PSU A and one on PSU B.

newegg has a good deal on dual-PSU capable cases you should check out.

That's absolutely not true. Where'd you come up with that?
How can I say this nicely:

He's f*kd in the head...

:lol:

 

[Cheese]

Yes it is true. It is posted on nvidia's site at:

http://www.nvidia.com/dualpsu

They recommend dual PSUs for your dual GPUs.

At least 500W a piece.

The 7900GT series has a faulty capacitor installed on the memory-GPU bridge that requires two seperate power chains derived from seperate power units when in SLI mode. It's all on that website.

Newegg has good dual-PSU capable cases. $150-200

 

[Gary_Busey]

Yes it is true. It is posted on nvidia's site at:

http://www.nvidia.com/dualpsu

They recommend dual PSUs for your dual GPUs.

At least 500W a piece.

The 7900GT series has a faulty capacitor installed on the memory-GPU bridge that requires two seperate power chains derived from seperate power units when in SLI mode. It's all on that website.

Newegg has good dual-PSU capable cases. $150-200

"Page Not Found"

Way to be a douche.

 

[prozac26]

"Page Not Found"

 

[Cheese]

Really?

I thought Quake 4 was FAR better than Doom 3. I don't know why you like Doom 3 better. Quake 4 at least had a flashlight on the weapons!

To each his own I guess!

 

[rahul_cracker]

hey cheese the link says page not found or old link how can the information be verified

 

[Gary_Busey]

hey cheese the link says page not found or old link how can the information be verified

He's lying, thinks he's being funny. Just ignore everything he says.

 

[echoplex]

OK but how about my actual problem??? Does anyone have any idea what's going on? I don't want to hear garbage about how every 7900gt has a defective capacitor...that's completely redic. I would really appreciate some ACTUAL clues and suggestions to move this thread forward...thank you very much in advance for your help.

 

[mad_fitzy]

Get at least a 550 watt. And I think what cheese may mean if he isnt being a toss is that you need to connect each video card so a power connector on a seperate chain to eachother. And according to this, you need more amps on your 12v rails.

 

[Gary_Busey]

I wouldn't be so quick to say it's the PSU, although it could be. I've had, and have heard of, several problems with BF2 crashing on peoples computers, so much so that EA issued a public letter stating they were aware of the problem and apologized for how badly the game runs on so many machines. You might want to try the BF2 forums at EA and see if anyone over their has similar problems before your drop $80 on a new PSU.

 

[echoplex]

80? Try 200...lol Yeah...I'lll go look at the BF2 forums and see if I can find something. Never thought of that...thanks

 

[Gary_Busey]

80? Try 200...lol Yeah...I'lll go look at the BF2 forums and see if I can find something. Never thought of that...thanks

Oh yeah, you're in Canaduh.


Ha, Canaduh, I just made that up. Man I'm hilarious.

 

[TheGreatGrapeApe]

Ha, Canaduh, I just made that up.

Nah it's old, older than me (Heck - I've had Cana-D'oh! as my location for year, and that's an adaptation of the Cana-duh. :mrgreen:

Man I'm hilarious.

No, no you are not, that is not true, you are certainly unfunny, very un hillarious........... and so's your mom! :tongue:


Now as to the original question it sounds like PSU or perhaps there's something in BF2 stressing your rig in such a way as to cause it to fail at your clock speeds (check if bringing down the speeds a fraction make a difference), not all OCs react the same to all games, as we saw with the launch of D3 showing alot of people their previously believed stable OCs weren't. Check the lower speeds, see if that helps much. The problem is that the lower speeds also draw less power so it might 'fix' both problems by doing so so might not add too much insight, but might give you a better idea.

As for Cost, you can get a solid 550-600W PSU for about $125 in T.O. so depending on your location, I'd think about $150-ish, which should be ok for someone with an SLi rig. The biggest issue will be finding one that fits if you have dimension issues (I prefer the 7th dimension).

Not much else to do, but clean power along 2 separate rails is a good plan of attack, jsut be sure you can return the PSU if it doesn't fix the problem, heck you could get one and test it outside of your case regardless of fit and see if that clears things up, and if it does then you know the source of your problem and then can worry about the asthetic and dimensional issues of it.

 

[w00ten]

I'm amazed that up until now theres only been a brief mention of the overclocking. Overclocking is notorious for giving the blue screen of death. Perhaps it is just the way BF2 is sending instructions mixed with the overclocking thats doin this. Set back to factory defaults and see what happens. Then gradually set the cores back to where you have them and test it along the way. See if you can find a correlation with the overclocking and the blue screen of death. The dual PSU is absolute BS and nothing but. I have an almost identical rig to you. Athlon 64 X2 3800 and dual 7900 GT's except mine are at factory settings and my PSU is 550W. I have had not a single problem at all. The rig runs like an absolute dream on everything that I play.

 

[TheGreatGrapeApe]

Yeah and the problem with trouble shooting it i that OC'ing does increase power demands, so he's obviously on the brink of something, but the questions is, is it the brink of power requirements or the brink of card stability. Bringing the clocks down to factory will help both, but if he likes the boost of the OC and it's stable but just needs more juice, then the new PSU would help, but like I said, you gotta test to be sure.

Personally I'm with you, drop it down a few mhz see if it's stable, if so, then leave it at that setting for BF2 and up it for other games using a dynamic OC profile when launching the games.

Just my two frames' worth as always.

 

[Gary_Busey]

I'd be sold on that if it weren't for the fact that it only happens in BF2. That makes things a little weird. Kind of like when Ape's mom showed me her penis.

 

[TheGreatGrapeApe]

I'd be sold on that if it weren't for the fact that it only happens in BF2.

Except for some games stress setups diffferently like I mentioned about D3, things can work perfectly in 99.999% of the situations and then that one app requires more resources in some area and poof instability. D3's probbably the most notorious example, but different games have cause weak point in other areas and BF2 IS a VPU stressful game, but still it's just a suggestion, the only way to find out for sure is to test.

That makes things a little weird. Kind of like when Ape's mom showed me her penis.

Nah, obviously once again in one of your methed up hazes you were hiting on your fellow inmates again. I mean seriously it's impossible mom had her peni$ removed long ago.

 

[Gary_Busey]

That's disturbing.


I agree, but he also said he can play Oblivion on almost everything max and it's stable as can be. I think we can all agree Oblivion is pretty VPU intensive.

 

[TheGreatGrapeApe]

Oh I agree that Oblivion is very VPU intensive, just that perhaps it's something different being stressed, there were alot of stressful apps out there when D3 shipped, but only D3 was causing all these problems, and to this day it's still not as stressfull as some parts of FartCry, but it just stressed the cards in a way they'd never been before. That's all I'm say not A>B, just that for some reason B is causing them problems.

 

[echoplex]

I'm amazed that up until now theres only been a brief mention of the overclocking. Overclocking is notorious for giving the blue screen of death. Perhaps it is just the way BF2 is sending instructions mixed with the overclocking thats doin this. Set back to factory defaults and see what happens. Then gradually set the cores back to where you have them and test it along the way. See if you can find a correlation with the overclocking and the blue screen of death. The dual PSU is absolute BS and nothing but. I have an almost identical rig to you. Athlon 64 X2 3800 and dual 7900 GT's except mine are at factory settings and my PSU is 550W. I have had not a single problem at all. The rig runs like an absolute dream on everything that I play.

Sorry, I did forget to mention that the cards are at factory clocks...they are the superclocked KO EVGAs. I have read so much documentation regarding the poor quality of these cards in previous batches. These cards that I bought are from the new batch after the tweek in quality control performed by EVGA.

 

[enforcerfx]

I guess the latest version, v1.03 i think it is, is suppose to be bugged. 1.4 is supposed to have better results. I have 1.3, and sometimes in the middle of a game, it'll say "Lost Connection" and force quit me out of the server. May want to up the PSU power though too. I dont know how cheese thought you needed 2 PSUs to run 2 video cards. Thats garbage, dont listen to him.

 

[echoplex]

Well...here's an update:

I checked the PSU while under full load in oblivion and BF2, also 3D mark 06 and the 12V rails dipped down to 11.88V when the fans on the vid cards kicked on initially but when in game, the 12V rail was at 11.93V to 11.98V right through the test. These numbers are well within the alotted percentage to consider a power supply stable. Not the best, but it's there. The current draw is obviously within the spec of the PSU as the voltage drop doesn't show huge fluctuations or signs of compensating for overcurrent through voltage.

One more thing, though. After running "Deep Freeze" for the second time in 3DMark06 with antialiasing @ 8xS, I noticed artifacts. Remember, my GPUs are at the factory clock settings of 580Mhz. My GPUs at full load read only about 70 degrees or less on a BAD day. I've recently replaced the stock heatsinks and fan with Zalman 700AlCu GPU coolers and ramsinks.

I went into Oblivion after a restart and noticed tearing on the guards and other characters. I'm POSITIVE this is from the RAM getting hot and not the GPUs as they still remain under 65 degrees with the Zalman cooler. Replacing the coolers gave me piece of mind that the factory clock settings were going to hold stable with the new cooling options. The airflow in the case in good with 3x120mm fans. I set the drivers back to "application controled" under antialiasing and Oblivion seemed to run fine again... Don't forget, I'm gaming at 1920x1200 in oblivion...

My question is this....If infact it IS the memory on the 7900GT KO super that is causing oblivion to artifact like this, I'd like to provide better cooling through the case. Are there any brackets out there that can accomodate another 120mm fan in the optical drive bay section of the case? I mean, I'd like to install a fan in the place of 3 expansion bays. If not I think I'm going to try and make a bracket myself, and drill the bay covers out to allow air through them and do it all professional-like....

Well...I think that just about does it for the update...hopefully I can get everyone's opinion again regarding maybe the airflow, the cards or reassurance that the PSU is up to the task of powering my system....

Thanks again folks.