Here is the breakdown of the performance difference between
single and dual core on 3D Mark 05 individual Tests:

% Dual Core Faster than Single Core
with Beta 81.26
Game Test 1
6%
Game Test 2
9%
Game Test 3
3%

What a difference from the singe card tests. Now it could either
mean that these drivers uses the second core to help “facilitate”
the SLI rendering, or that the drivers actually optimizes specifically for 3D
Mark 05. Being the skeptical guy, I wanted to see if the drivers “watches
out” for any running of 3DMark05.exe files. So I renamed the 3DMark05.exe
to dude.exe. 3D Mark 05 will still check for 3DMark05.exe before it runs so
you will need to first copy off the exe file, rename the current file to any
name you wish and paste back 3DMark05.exe.

7 NVIDIA Forceware 81.26 Beta: Single Core vs Dual Core

Then I ran my renamed file dude.exe.

The score actually dropped a big margin, from 8470 to 7441
on the Dual Core with Beta 81.26. The main drop occured in Game Test 3 which
dropped from 58fps to 39fps.

It is not the time yet to jump the gun and call it a specific 3D Mark optimization.
It could perhaps be a different SLI rendering mode used that is specific to
applications. So we decided to see if it runs on a different SLI rendering mode
when we run the renamed file.

We have an artifacted 7800GTX that became this way from extreme overclocking.
So we run one good card with one artifacted card to pick out the SLI rendering
mode.

We immeditaely recognized that 3D Mark 05 actually runs in SLI
split screen rendering mode when the file is renamed. This is due to the fact
that only half of the screen is artifacted while the other half is perfectly
fine:

8 NVIDIA Forceware 81.26 Beta: Single Core vs Dual Core

 

Now, we run the actual non-renamed 3D Mark05 file. The artifacts
immediately filled up the whole screen.

9 NVIDIA Forceware 81.26 Beta: Single Core vs Dual Core

This means that normally 3D Mark 05 runs in Alternate Frame Rendering and switching
over to Split Screen will drop scores a lot. The funny thing is that with the
81.26 drivers, even selecting the 3D Mark 05 profile still renders SLI in split
screen when we run the renamed file.

We tested out with the old 77.72 drivers and it is the same scenario. This
shows that SLI rendering profiles are very important to performance and are
truly application specific.

In any case, the Dual Core certainly helps out performance in SLI mode with
the beta 81.26 drivers while the new drivers do nothing much for Single Core
in 3D Mark 05.