I'm going to overclock my stock e8400 to 3.6ghz if I can. Folks said this was possible on stock cooling, but I'd like to be as careful as possible.
Should I replace the existing heatsink or simply add a fan to an empty fan slot on my case that's near the processor?
Adding a fan would be easier, and thus preferable, but may not have the benefit.
My case is pretty huge, so heating isn't really a problem right now.
Adding a fan , pointing it at stock HSFan , will not do much.
3.6 should be fine with stock heat sink.
Reasons: Dual cores just run a little cooler than quads would.
3.6 should be doable without much voltage increase if any.
Prime 95 MAY bring the cpu up to the 70's in stability testing.
But normal use it will probably stay under 60 all the time, Which is fine.
What are your temps right now ?
Use HWmonitor to see both core temps and Ccase temp.
Try OC using stock HSF first and closely monitor the temps. If it goes higher than your target temp during the stress test then maybe its time to buy a new HSF. I agree that adding case fan to the side even pointing it directly to the stock HSF will not help. I tried it before.
my e8400 (on stock cooler) goes to 79 degrees when running stress tests: in games it goes to 62 degrees with an idle temp around 50, find those temps and if you're not ok with it get a cpu cooler like the hyper 212+
I took off the old heatsink and the themal contact has totally hardened on both the chip and the heatsink. A. Is this normal? B. Should I apply a new coat whether I buy a new heatsink or not? C. Should I buff the old stuff off? I will probably by a new heatsink because the old one is completely full of dust.
Yes. You should clean the old thermal paste off the chip and apply new thermal paste when you install the new heatsink. The new heatsink usually come with a sachet of thermal paste. You can apply this if you are not going to OC heavily. But if you plan to OC, then use better grade thermal paste such as arctic silver.