You are CPU limited. The card you had was probably a perfect
match for the 1.3GHz processor. The latest Tomshardware charts
show CPU limitations, even on an ATI9800pro, when using an
Athlon64 4000+ processor. Your processor is 3x slower than that,
so until you do something about the processor, no miracles
will happen.
Performance depends on each subsystem. A slow subsystem forms
a bottleneck, the "rate limiting" step. Say you bought a length
of fire hose, some adapters, and a 1/2" garden hose. When
connected together, the end result is, you don't get very
wet, very fast. Even though you did use a length of fire hose.
As an example, look at the two charts here:
http://graphics.tomshardware.com/graphic/20050705/vga-charts-pcie-05.html
There is a 1024x768 "low resolution" chart and a "1280x1024"
chart. At 1024x768, from the FX5900XT card upward, there are
no additional FPS to speak of. The reason is, the Athlon64
4000+ simply cannot produce enough data to keep the video card
busy rendering frames. Now, when the resolution jumps to
1280x1024, there are more pixels for the video card to process.
At that resolution, a 6800GT is the right match for the
Athlon 4000+ processor being used. Using more video card than
that, doesn't appear to make big strides in performance.
In your case, the processor is 1/3 of the processor used in
the charts. No matter what video card you used from the
Tomshardware charts above, that video card will be operating
in the "flat zone", so no improvement.
There is an older, better chart for describing this problem.
Take a look at this one:
http://graphics.tomshardware.com/graphic/20030120/vgacharts-04.html
In that case, an Athlon 1000 owner tries different new video cards.
The grey bars show the slow rate of increase in performance, for
the expensive video cards being used. The curve for the Athlon
2700+ shows more steepness, meaning the more expensive video cards
are doing something, due to the faster processor.
For processor upgrades, your officially supported options are here:
http://support.asus.com.tw/cpusupport/cpu_support_right_master.aspx?type=1&name=P4T&SLanguage=en-us
An unofficial option, is this Upgradeware 423-478 adapter:
http://www.upgradeware.com/english/product/p478/performance.htm#p478oc
You can get a 2.8GHz/FSB400/512KB cache S478 processor here $189
http://www.powerleap.com/Processors.jsp
Depending on your budget, a platform change might help, at least
in terms of allowing faster processors to be used. The price of
some of those options is pretty steep. You might consider using
DDR memory, as the price will not be going up for another month
or so (but a price increase is coming - some plants are switching
production from DDR to flash or something).
HTH,
Paul
