8800 GTS Sli

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compwizpro

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Apr 26, 2008
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I have a couple questions about sli setup.

I recently picked up an evga 8800GTS SSC 640MB to go along with my xfx 8800GTS Extreme. They both have the same clock speeds at 576mhz and memory speeds. I am running on an asus p5n-e sli with a q6600 and 4 gigs of ocz sli memory at 800mhz powered by a 600w ultra x finity power supply.



Recently the fans on my power supply suddenly automatically run at full speed. Everything seems to be fine exept its noisy (dual 80mm fans) and it sucks all of the air out of my case to fast.

The power supply has dual rails 12V1 @ 18A and 12V2 @ 20A. I looked in the manual and it says that each PCIe power connector gets its own rail so each video card gets its own rail.

When both cards are in Sli enables fine but the top most card runs extremly hot. It idles around 80-85 degrees and runs around 95-103 degrees when under load while the bottum card only gets to about 76 degrees.(the top card was original card and only ran at 75 degrees before the other card was installed). Also my case is a Xion Solaris Green.

Do you think the power supply is sucking all the air out to fast and there isnt enough air getting to the cards?(when i pop the side pannel off, hot air starts blasting out of the cards vents on the back but then the motherboard starts running hot).

Also without sli I scored 10500 on 3dmark06 and with sli i scored 12500 on it. Do these scores seem right?

Sorry that this is a long post but I am new to this whole sli thing.

Thanks
 
I dont know about the scores, but I can say you should upgrade the PSU, its running its fans hard because its being taxed to its limits. The top video card is probably not getting enough air because of the card below it and the heat rising from the card below it. The PSU pulling alot of air may or may not be adding to that.
 
The power supply fans started spinning fast a day before it put in the second cards. It happened after I tried updating my bios from the 0903 to the 1001 version but failed.

I was thinking of getting one of those ultra bay psu's that add on extra 12v amperage.

I also read that some cards recognize the lack of power from the power supply and will throttle the speed of the card back so it doesnt trigger the 20A limit. Do you think this might be the case and if i upgrade my psu do you think my cards will run more effitiently?

Thanks
 
that quad wont oc for crap on that mobo will it? I had that setup for 1 day and sold it off. i cant have a good quad go to waste on that mobo..... just venting. your scores may be inline with that cpu near stock speeds.
 
The board uses AI overclocking and can only do it by percentage. Also it links the fsb and memory so it overclocks the memory aswell which makes it incredibly unstable if you dont have good ram.
 
It's a rumor that you need a huge power supply for SLI. Those estimations take into consideration the people that have a bunch of drives, lights, fans etc ... One guy did a test with a basic system w/o a bunch of shit in the case, sli was I believe 8800GT and he was only drawing 400 watts.
 
Also what is the recommended maximum safe temperature the 8800 gts should be idling at and under heavy load(3dmark, etc)?
 
That's not very much on the 12V rails. By contrast, the Corsair 650TX has one 12V rail with 52A. It is an Ultra though.

As far as possible performance issues, I'm not surprised. The eVGA 8800GTS SSC is 96+ SP (aka 112 SP) while the XFX is 96 SP.
 
Do you think that a bay psu would be a suitable upgarde that would give additional power?

Also would the difference in streaming processors compromise my sli setup or wouldnt the system distribute the load evenly via the sli bridge?
 
compwizpro said:
Do you think that a bay psu would be a suitable upgarde that would give additional power?

Also would the difference in streaming processors compromise my sli setup or wouldnt the system distribute the load evenly via the sli bridge?
Click to expand...

I've never used a bay PSU. Hopefully someone who has will chime in.

I'm not sure, that's where it gets difficult. They definitely have a different amount of SPs, and I haven't seen any proof one way or the other whether they can coexist properly.

I would try playing some games while running fraps or check by simply whether they feel smoother with SLI or without. You won't see a 100% difference obviously, but you should see something unless you're playing at a low resolution.
 
I have a new question now.

When I have the two cards(xfx 8800gts and evga 8800gts) in sli, I go into everest and under the video cards it says that my xfx has a core clock of 1MHZ and a memory clock of 2MHZ. It also says that the bandwidth is 128MB/s and somthing like 16 texels per second. However for the evga card all of the specs are acurate.

Is this just an inacurrate reading in everest or is my xfx card being slowed down by a possible lack of power or somthing else. I also tried to enable SLI Broadcast Aperture to see if that did anything.

If anyone knows what that is let me know.

thanks
 
Your scores seem a tad low. I have two 8800gts 640mb (One XFX, the other BFG), and score 15000 in 3DMark 2k6 (With a dual core CPU).

Regarding your power issues, I would strongly recommend picking up a quality unit to safeguard against any future problems. I blew out a Seasonic 550W PS with my rig, and have since upgraded to a PC Power and Cooling 750W unit (with no problems to report).

Use GPU-Z to ensure that both of your cards are running at their proper frequency.
 
Brampton_Boy said:
Your scores seem a tad low. I have two 8800gts 640mb (One XFX, the other BFG), and score 15000 in 3DMark 2k6 (With a dual core CPU).

Regarding your power issues, I would strongly recommend picking up a quality unit to safeguard against any future problems. I blew out a Seasonic 550W PS with my rig, and have since upgraded to a PC Power and Cooling 750W unit (with no problems to report).

Use GPU-Z to ensure that both of your cards are running at their proper frequency.
Click to expand...


Brampton,

Can you tell me you 3d settings configuration you have in your nvidia control pannel?

I want to know what settings you have that enable you to get that higher score. One of the things I want to know is what sli rendering mode you have set? If you could tell me what you are running also I would appreciate it.

Thanks
 
Driver Version: 6.14.11.7516
3D Settings: Let the 3D Application Decide
SLI Rendering Mode (For 3D Mark 2k6): Nvidia Recommended (SLI)
OS: Windows XP SP2


System Specs:

Core2Duo@3400Mhz
4Gig DDR667@750 RAM
Asus P5N-E SLI (650i)
2x8800GTS 640MB SLI
 
Brampton_Boy said:
Driver Version: 6.14.11.7516
3D Settings: Let the 3D Application Decide
SLI Rendering Mode (For 3D Mark 2k6): Nvidia Recommended (SLI)
OS: Windows XP SP2


System Specs:

Core2Duo@3400Mhz
4Gig DDR667@750 RAM
Asus P5N-E SLI (650i)
2x8800GTS 640MB SLI
Click to expand...


Brampton,

Do you think your core 2 duo clock at 3.4ghz is giving you an extra 3000 points?

I am only at 2.4GHZ so maybe thats where your getting more on me.

It seems like your running close to the same system as mine dispite the overclocked processor.

Thanks
 
What is your CPU score in 3D mark?

I get 3017 with my system. Generally speaking, most quadcores that I have seen score 4000+ on the CPU benchmark
 
I got 3302 on my 3dmark test for cpu.

Could you post your graphics scores as well?

Mine were 4487 for S.M. 2.0 and 4402 for SM 3.0.

If you scores are higher than that then that would probably mean that your sli setup is giving you the extra points and that is what I want to know.

Thanks
 
compwizpro said:
Do you think that a bay psu would be a suitable upgarde that would give additional power?
Click to expand...

Never. You can usually find a good quality PSU for the price of those bay PSUs. So no need for those bay PSUs at all. Just invest in a better PSU. Note that everyone here has said "better" not bigger PSU. While 600W is more than enough for a SLI setup, that's only true if it's a GOOD quality 600W PSU.
 
compwizpro said:
Also what is the recommended maximum safe temperature the 8800 gts should be idling at and under heavy load(3dmark, etc)?
Click to expand...

The card(s) will throttle at about 120-130C. You can see the temperature using Nibitor.
 
Ive got another question.

I have identified that the evga card runs a lot hotter than the other card I first had(idles at 70c). I my case laying on its side with the top side pannel off and 80mm fans sitting on top of the two cards sucking the hot air out so the heat cant rise into the other card. I monitored the evga card using everest and the memory, ambient temp, and the gpu temp are all withen the 40c-50c range but the gpu diode temp is still around 73c idling while my xfx card has a gpu diode temp of around 54 degrees with similar temp readings for other sensors. Also this evga card has probably only had about 4 - 5 hours of operating time in my case so is it possible that the thermal compound hasnt bonded yet or somthing to that effect?

By the way I am getting a replacement psu from Ultra and I believe this psu will perform bettter than my last one.

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3276573&CatId=1483

Thanks
 
compwizpro said:
Also this evga card has probably only had about 4 - 5 hours of operating time in my case so is it possible that the thermal compound hasnt bonded yet or somthing to that effect?
Click to expand...

Could be dust. Clean out the eVGA card.Also, it could be different fan profiles. The XFX card probably has its fan kick in sooner while the eVGA's fan doesn't kick in till the temps are much higher. Also that XFX card could be getting better airflow that the eVGA. Swap the video cards around and see if the temps changes.

compwizpro said:
By the way I am getting a replacement psu from Ultra and I believe this psu will perform bettter than my last one.

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3276573&CatId=1483
Click to expand...

Hmm, only 38A on the +12V rail. Pretty pathetic for a 650W PSU considering that the Corsair 650TX 650W and Corsair 550VX has 52A and 41A on the +12V rail respectively. But it's Win-tech made, so for your needs, it should be fine.
 
The evga card is brand new so I dont know about dust accumulation.

I also watch the fans as they boot up and they both first rev up for about 2 seconds and then calm down to the default 60 percent.

I have swapped the cards around many times and have tried a variety of airflow variations including hooking up a dryer air duct to the back of the grills and hooking it up to a blower that moves 343 cfm of air and that managed to bring the temps to around 60 degrees celcius but that was noisy.

Also any tips for configuring the 3d settings in the nvidia control pannel are greatly appreciated.
 
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