I'm looking to purchase the Zalman ZALMAN CNPS9900 NT 120mm 2 Ball CPU Cooler because I've had great success with their products in the past, plus its fan speed is controlled by the mobo. It comes with its own thermal gel (High-performance thermal grease is available to ensure a perfect combination between the copper base and CPU for excellent heat conduction.)
My questions are:
*Should I be concerned with space with the cooler? I have an Nvidia 560ti vid card in the PCIe x16 slot
*Should I use the included thermal gel or get Arctic Silver 5?
You can certainly use the stuff that comes with the Zalman cooler. It will likely fit in the case, as their coolers are smaller than most 'tower' type standard coolers.
If you go with a different thermal compound, I'd suggest something other than AS5. Why? It has an overly complex curing method to reach optimal temps, plus it's electrically conductive. Something like the Gelid GC-Extreme or Shin Etsu G751 compounds have no curing time and aren't electrically conductive at all.
Read this page from an 80-way comparison. In the chart, the best ones are at the bottom.
Either you didn't mount the cooler correctly or you are heavily over-volting and/or overclocking the CPU. It shouldn't be running at 82ºC otherwise.
TjMax is the maximum per-core temp. Sandy Bridge is rated for TjMax of 98ºC, and will start auto-throttling in the low-90sºC to save itself.
Edit: Unless your ambient temps are super high right now.
My 2500K overclocks to 4.8GHz at about 1.504v, and the temps peak in the low-70sºC during an IntelBurnTest v2.50 50-run Maximum Stress test. That was using a Scythe Rasetsu cooler, which isn't all that great.
I would actually bring the computer into the tech shop where you bought the processor. See if they can re-mount the heatsink and what the temps are. There may indeed be something wrong with the CPU, but this would be the first time I've heard of a problem like this being the CPU's fault. If they get the same temps, maybe they'll replace the CPU for you.
I've had the CPU for about a year and a half, purchased from Newegg. Just recently got into computer gaming again and with that the proc temps went up. I'll just let it run, I'm not going to sink more money into it.