Remember thoguh, this test was using an Athlon X2 3800+/8800 GTS vs. a Core2 duo E6600/8800 GTS.
The Athlon X2's might be cheap, but they're a dual core CPU with a decent sized cache.
A sempron will be a single core, and have a much smaller cache to boot. might not get the same results you're looking for. I'd be hesitant to pair an 8800-calss card with anything less than a full Athlon64 at least...
I have just put an Asus 8800GT (still stock speeds until I get some temp readings to work by >_< - the new cooler design ones give out no temp readings currently and no fix know from Asus yet...) in my system replacing the X1800XL @ 567/630
my Opteron is equivilent to a AMD 64 4000+ (single core)
Some B4 and afters:
UT3 Demo avg play readings (Fraps):
X1800XL - 1280*1024 (detail settings 4,2 in setup) = 28fps
8800GT - 1600*1200 (5,5) = 50fps
8800GT in lower settings also 50fps
Crysis avg FRAPS:
X1800XL - 1024*768 - all Medium settings - no AA - 14fps --- NOTE missing display of pretty much everything cept terrain and water LOL
8800GT - 1280*1024 - all High settings - 2x AA - 30fps
CS:S Avg FRAPS
X1800XL - 1280*1024 - all high settings - 45fps
8800GT - 1600*1200 - all high settings - 16x AA - 45fps
8800GT - 1280*1024 - all high settings - 50fps
X1800XL - 5996
8800GT - 29567
X1800XL - 6370
8800GT - 11460
X1800XL - 2842
8800GT - 6243
Am really pleased with this upgrade - show how much my CPU is holding me back though!!!!
am upgrading to a good deal on the Q6600 / P35 in Jan / Feb or maybe the new chip if its much better or a good deal ^^