What is happening here is that your desktop size in the game is different from what youw windows desktop is. What you need to do is set your Windows desktop to the resolution that you play CS in, and then manually adjust the refresh rate to what you want. Then you can set your desktop back, and windows will remember the refresh rate for the other setting, and use it when you are gaming.
It is possible that your video card will not do 85 at the resolution you are gaming at, but if it will, then the manual adjust will work fine. I've had to do this in one rig where a marginal monitor vibrates @ 60Hz, and needed to be set so that 60 wasn't the refresh rate for any resolution I used.
Free advice, and worth every penny.
What fps are you getting now and what vid card and OS are you using. Also what resolution? I use "net_graph 3" in the console to check fps. Go into your CS folder, you may need to adjust the "fps_max." It may be set to 75.