Minimum Processor for SLI (AMD)

[dklingen]

I don't recall seeing this anywhere. But has anyone built an SLI setup using the Athlon 64 3200 CPU with dual 6800 GT GPUs?

I read at Hexus.net that they recommend the minimum processor for a dual 6800 GT setup be an Athlon 64 3500. This is almost $100 more for 200MHz clock speed. In looking at the Half Life 2 CPU review at Anandtech, the framerate difference between the 3200 and 3500 is about 3-5 fps depending upon the test. This is not worth the extra $100. I do realize that their test was not using SLI, that is why I am looking for help.

Thanks!

 

[stevty2889]

A 3200+ wiinchester would easily overclock to 3500+ speeds or more anyway...

 

[SrGuapo]

If you have dual 6800gts, I assume you are going to be cranking everything (resolution, AA/AF, etc.) way up. This will bottleneck your cards anyway, so yhou should be fine with a 3200+. If it is really a problem, just OC the CPU to 2.4 GHz (a little less than a 4000+ due to lower L2).

 

[miketheidiot]

If you have th $$$$ to go SLI, get a good HSF (XP-90, zalman?) and OC.

probably 90% will hit 2.5ghz.

 

[Elfear]

If I get a few minutes I'll run some tests for you. I'm using a 3000+ with dual 6800GTs and it seems to be fine. I can run some timedemos at stock and oced to 2.5-2.6GHz to see what the difference is.

 

[ribbon13]

Try underclocking and see if it's sufficient... that would be the real test.

 

[MisterChief]

CPU bottlenecks are blown WAY out of proportion. If you are going to seriously use two 6800GTs, a 3200 would be just fine.

 

[dklingen]

Everyone,

Thank you for the feedback!

I would also be very interested in additional feedback from Elfear. Are you happy with your SLI setup? Any test results you can provide would be great.

 

[Elfear]

I'll try to get those today. I've been fighting some weird bsods while ocing the cpu so I haven't had much time to run any gaming benchmarks, just a few synthetic ones. 3DMark scores are spot on but than again you can't play 3DMark so I'll let you know when I get some real benchies.

FYI- Probably an obvious problem but if you go SLI than make sure your case has very good ventilation. I have six case fans, including a 105cfm 120mm fan in the side of the case right over the video cards, and my case temps have gone up considerably over one card. I'm not saying you need a gazillion case fans (I probably went overboard) but it's something to consider. Especially if you plan on ocing.

I still need to try a few different case fan configurations to see which would vent the best. If I can build a really inexpensive watercooling kit I might try that.