Call of Duty: Black Ops extreme performance issues

I got this game and installed it on my iMac using Bootcamp. You can see my specs to the left, late 2009 model iMac. I've been doing a lot of gaming on my iMac with Bootcamp, I played Modern Warfare 1 & 2 and I've been playing some games that came out this year like Starcraft 2 without many issues, so I'm feeling like my rig is still pretty good, obviously not the best it could be... it's only a year old after all.

After playing around with the graphical settings extensively, I can't get Black Ops to run at an acceptable level. Even with everything set to lowest and resolution on 800x600 resolution, the FPS is still horrendous. The strange thing is it runs almost as poorly in my monitor's native resolution (2560x1440). When I try turning the other settings to higher levels, however, my computer can't even begin to handle it.

Any ideas? I'm about to return the game this feels so hopeless. If only I could afford an xbox or playstation...

Well I would say make sure you have the latest drivers first.

Then check out: GameSpot Forums - Call of Duty: Black Ops - lag and low fps and frame spikes Call of Duty

Someone says it's being discussed in here as well: Weird system resource usage = heavy lag - Page 4 - Steam Users' Forums and I guess they suggest running Steam in Offline mode for single player

CoD Black Ops

How did you install CoD Black Ops? With windows parallels I install it with no problem but on BootCamp I always get an error on instalation via daemon tools, in the file iw_22.iwd always says "can't read from source, file may be currupted", I already download it again 2 or 3 times and I rechecked that I could still use the same file with no error via windows parallels! I'm driving insane because in Parallels you don't have a good performance to play for obvious reasons but I can't make it work on BootCamp!!! I'm using Skidrow version, 7,29Gb, am I missing something?!!

thanks in advance