Counter Strike (1.6) lag

[#1]

Anyone play?
For the last few months if I play CS (1.6) using Windows XP I get
horrible lag and joltiness sometimes, particularily when smoke greandes are around or on the map. (Not FPS lag)
I (for a laugh) installed it on my Vista Ultimate partition, updated the Ati drivers to the latest, and it actually plays better! There is no lag whatsoever, I've tried the same servers on each OS too....
Any ideas? Could it be rwin settings or something? I've used
TCP optimiser on XP to set some settings up.

[#2]

Smoke lag? Give this a try:
Setting "fastsprites" setting in CS to help with smoke lag:
1. Get into a Counter-Strike game.
2. Pull down your Half-Life console by hitting your "`" key.
3. In your Half-life console, type in:
    fastsprites "2"
4. Then, hit your keyboard's ENTER key.
Note: fastsprites "0" is the default setting, also there is a mid way setting fastsprites "1". There is also a way to change this setting in the "Customization" "Configuration" Menu.

[#3]

Tried that, and many other commands with no joy.
I installed the latest Ati drivers on my XP partition, and that fixed it!
I always use Omega drivers as they perform better then
Ati ones, I'll leave the Ati ones this time as they work fine
Thanks.

[#4]

whats your pc spec? cs 1.6 shouldnt need such a powerful machine.

[#5]

Not amazing, but not slow. I can run a very playable Crysis on all medium settings.
(3500+ at 2.4ghz, 2GB corsair ram, Ati X800XT)
The problem has since re-occured when I play it on XP, which makes no sense. So having to play it in Vista and dropping about 30 fps
Runs about 150fps in Vista when I would get a solid 199fps in XP.
CS: Source, however runs super well!

[#6]

I was gonna say graphics drivers. I was having the same issue on portal, updated the drivers (well backdated actually, but still) and that sorted the issue. Might be worth trying some different ones, maybe the omega drivers if you use ATI?