Recently, I was reading a thread on a different subject and stumbled across some info on ATI cards having a lower detail distance than nvidia in Half-Life 2. It came to light when comparing the X1800XT with the 7800GTX and someone noticed some items that were visible in the nvidia screenshot were missing in the ATI screenshot. They also mentioned that the setting seemed to be that way for the X1800s, the X850s and possibly all ATI cards.
The setting is: cl_detaildist
and for ATI cards it apparently defaults to 1200
while for Nvidia cards it defaults to 1600
Just on a spot check, this caused a 10 fps hit on the 7800s (121fps at 1200, 111fps at 1600) that was most noticeable with vegetation in the scene (in the limited areas I've checked).
I believe they have sent a question to Valve asking why this is the case but this is really bugging me. It seems too shady and obvious so that there must a reason for it. So, anyone have any info on this or maybe why it would be done?
1600..........................1200 (notice missing grass when at 1200)