A resident by the name of Nala Spires did some testing to see what affects the SL Viewer performance the most. You can read about his test and the results here: CPU / RAM/ VGA what sl likes More ? ((attempting to answer that ! ))
She used this viewer: Windows 7 professional 64bit firestorm Viewer v220.127.116.11744
She also used FRAPS to benchmark the performance. FRAPS slows my system so I would expect the numbers to be a bit lower than normal.
A lot of the numbers make no sense to me. Since it is FRAPS I assume they were FPS numbers. But jumping around between 200+ and 20 seems a bit beyond anything that makes since to me.
I did read her Conclusions and they are interesting. Nala concluded memory speed had a significant impact on performance. Buying FASTER memory did the most for performance.
She concluded Hyper-Threading had no measurable impact. My experience is that Hyper-Threading does have a perceptible impact on rez time. I would agree that it has little impact on FPS. I am assuming she is talking about changing the Hyper-Threading in the viewer rather than forcing the viewer into a single core, which on an i7 is still capable of running 2 threads.
Of course disabling the GTX460 and using only HD Graphics in the CPU had a major impact. She tried under-clocking (slowing) the GTX460 to see how much performance decrease showed up. Slowing from the base speed of 34 FPS to 31 is an 8.8% slowing. That is from a 37% GPU slowing. Her conclusion that one won’t get much from a high end graphic card is probably right. Of course that is only for Second Life. Other games are more sensitive to the quality of your video card.
She concludes CPU speed makes a significant difference. Going from 3.5 ghz to 2.5 ghz is a slowing of 28.6%. It resulted in a 35.3% performance slowing. That matches my experience.
While she could not test SLI (using two video cards) the word I have from those using SLI is that it only improves render time not FPS. The extra card decompresses textures and not much more. But, that could change at any time.
It is an interesting set of measurements.
Thank you Nala.