Stock coolers aren't really made for overclocking, they are there to sustain temps for factory clocks. I would recommend spending 20 bucks on an aftermarket cooler, and enjoy the safety and piece of mind it will add.
You're welcome, enjoy your 6850, it can be pushed pretty well also. I would check out MSI afterburner for setting up your fan speed profile, and pushing your core clock and memory. Though I haven't had a lot of success with memory clocks, your core can be pushed farther than the crossfire 6870's I have from what I've read.
Pick a best answer, and cheers mate, enjoy your tower!
I'm yea... "just about 1GHz" is a huge number. Especially without some serious cooling. Why even bother with a midrange gpu
Budget is the usual response for going with a mid-range GPU. I have experienced large gains in the newer games with a quicker processor, with them seemingly putting more usage on the CPU for many things.