Can Someone help me understand my HL2 video Stress test results?

[JethroXP]

I'm using the Video Stress Test In Counter Stirke: Source.

I'm running a 128MB ATI 9800Pro AIW on a 2.4C P4 @ 2.7GHz

Video Options are:
1024x768
Full Screen
Normal (4:3)

Advanced Options are:
Model Detail: High
Texture Detail: High
Water Detail: Reflect World
Shadow Detail: High
Antialiasing Mode: none
Filering Mode: Trilinear
Shader Detail: High
Wait For vertical sync: Disabled

With these settings I consistently 47 FPS.

However if I change AA to 2x, filtering to 4x Aniso, and VSync to enabled, I then consistently get 67 FPS.

That seems completely backward to me. I would expect FPS to drop with those changes. Is the Video Stress test simply not reporting correctly?

 

[fromage]

Some people report that using AA and AF they receive higher framerates. I believe that only works on ATi cards.