小弟從Beyond3D看到的消息

http://www.beyond3d.com/forum/viewtopic.php?t=18170

ATI users might want to use the following command for areas of HL2 that are graphics limited (this might work with CS:S as well):

+r_fastzreject 1

The command enables Z fill geometry pass in order to speed up rendering of the full scene rendering pass - by default I'm told it is disabled for ATI as they had some slight performance drops in the more CPU limited levels, however there are gains to be had in graphics limited levels.

AFAIK this is presently a default option for NVIDIA (the testing was done back with 9800 / FX's), but should be updated as the default for both in the future.

------------------

文章裡頭是說﹐在顯示卡是瓶頸的情況下﹐+r_fastzreject 1 指令會開啟卡上的Z pass geometry功能﹐HL2和CS:S都適用。

此功能在NV顯示卡上已經開啟﹐所以沒效﹐Valve當初沒為ATI卡開是因為如果CPU是瓶頸﹐ATI卡的速度可能會有些許降低﹐未來HL2 patch會開啟此功能﹐喜歡嘗鮮的人可以玩玩看。