http://forums.techpowerup.com/showthread.php?t=69845

Cut from above link :

Very simple... when u select 8xAA in crysis.
For ati it loads 8xMSAA
and on nvdia it loads 4xMSAA & 8xCSAA.. its Nvdia trick... they spend a lot of money to make game developers support NV

You will find a file called FSAAProfilesDX10.txt and FSAAProfile.txt in config folder.
Delete both files and then you will notice, both cards will use MSAA

After deleting that file, you will not see 8xq 16x or 16xq
Even for Nvidia will only get 2x, 4x, 8x, which is real 8x MSAA.
now compair with ATI.
when that file is there. when you select 8x it lodes 8x msaa for ATI and lodes 4x msaa for Nvidia....

not only crysis... even in CMR grid you have simular file....

Lot of games in the market dose the same thing.. one other game is GRID. there are two files called hardware_settings_config.xml & Hardware-Settings-Options.xml and there you have same trick... and other files too


And when we do benchmarking. we should check using the MSAA to check the performance of the card. not CSAA or CFAA

CSAA nvidia
CFAA ATI

I tried this on my friends Nvidia and the first test was

Very High
8x AA which was using 4x sample and 8x quality
1280x720 and got 32 FPS

the same setting after using my file gave only 17FPS... he was shocked and started saying no i cannot accept this.. my card has a new technology and that is CSAA.. hehe

WHEN ONE CARD IS USING MSAA THE OTHER SHOULD USE THE SAME RIGHT
we cannot do racing with one car being a petrol and the other running in diesel