8800 GTX SLI Performing wierd need some help

[v3raxOC]

I have an Abit FP-IN9- SLI motherboard with an Intel 6600 Core Duo CPU. I bought a BFG 8800GTX 575/1800 and it ran awesome by itself on the mobo. 10,800 3Dmark2006 score. I am using Buffalo Firestix for memory.

A few days ago I decided to go the SLI route so I bought another BFG 8800GTX however, this one is the OC version (600/1800)

I also bought another PSU that I thought would handle the SLI config. (Coolermaster Real Power 850)

The PSU has 4 PCI-e 6 pin cables and I have 2 of them connected to each card.

I have 2 Seagate Barracudas (7200.10) runing in RAID ) and a sata DVD burner.

The problem is, when playing Call of Duty 2, I will be getting 250-500 FPS and then all of a sudden the FPS drops to 30-50 and then back up.

The last time I did it, I got out of the game and checked temps, The 8800 on top was at 79c and the one on bottom was 63c. Not really that high so I don't thinnk it was an overheating issue. I do have 2 120mm fans blowing on both.

Someone once told me that I should not use all the PCI-e connectors because they share a 12v rail, so I should just use 1 PCI-e connector and then one of the molex to PCI-e adapters for the second one on each card.

However, ecen after trying this, I still get the sudden drop in FPS.

Could the fact that I am using one card clocked at 575 and the other 600 be a the problem? or is 79c too high and its a heat issue?

Or is this PSU just not good enough for 2 8800GTX's

I am really puzzeled as to what is causing this.

Any ideas?

 

[v3raxOC]

Bump, come on I know there has to be someone out there that can suggest something

 

[theYipster]

Hi,

Most likely your hardware is fine. Keep in mind, however, that when using two differently clocked cards for SLI, both cars will run at the lesser of the two clock speeds. To remedy this, you will have to overclock your standard GPU to match the speeds of the overclocked card you bought. The temperature of 79c is within the normal range of a 8800 GTX card. These cards are designed to run very hot.

EDIT: For clarification, the difference in clock speeds is not the cause of your problem.

Anyway, the issues you are experiencing are probably driver related, and if you do a quick Google search, you'll see that many people are having similar experiences. One thing you didn't mention is the OS you're using. If it's Vista, then be warned that SLI is still quite buggy with all nVidia cards. (XP is a bit better, but even then, 8800 SLI is still a work-in-progress.) Make sure you have the latest drivers and have enabled SLI in the nVidia Control Panel. nVidia just posted new XP drivers to their website which supposedly resolve several studdering-game issues. If you're running Vista, I recommend checking out the new 101.70 drivers, which has been known to fix many issues and improve performance (on many people's machines.) The Vista drivers are not yet available for download directly from nVidia's website, but can be easily obtained at guru3d.com. Also, they've begun to appear from Microsoft via Windows Update.

Good luck, and remember to keep on top of driver releases. 8800-SLI performance is very much hit or miss right now, and even the non-beta drivers are still in a state that every user can easily have a different experience with them.

Mark.

 

[lopri]

8800 SLI performance scaling is horrible. (I even borrowed an 8800 GTX to test it out) Most of the times the performance was lower than a single card or the gain was like 10~20% in various games. (<-- Under Vista) It's nothing other than the driver immaturity. You just gotta wait.

 

[ScrewFace]

Everybody want go heaven but nobody want dead...Fred. (Marked for Death (Steven Seagal)).

 

[v3raxOC]

Originally posted by: ScrewFace
Everybody want go heaven but nobody want dead...Fred. (Marked for Death (Steven Seagal)).

Uhh, huh? What does that have to do with the price of eggs?