Had a 17" TFT monitor, and games ran really good without any lag at all at 1024X768 res.
And today i borrowed a 21" CRT from work, and the games run as crap on it

I have installed the correct driver for the 21" monitor, Checked the refresh rate, its supposed to run at 75hz or 85hz, i get the same "screen lag" at both refresh rate settings..
I even lowered the resuloution in game to 800x600 but it still wont run smooth?
I also lowered my desktop res to 800X600.
Any ideas?
I understand that my graphics card have to push mory polys to a bigger screen... So can it be that my computer cannot handle it?
As i said earlier, i had no problems with the smaller 17" TFT...
Any help would be appriciated.
Edit : heres the monitor
http://www.dealsdepot.com/Shop/Control/Product/fp/vpid/1325854/vpcsid/0/SFV/14930