Core i5-3570K it is supported only on rev E1 with atleast bios version 3705, on that motherboard...

What's rev E1? I flashed 3903 to get the thing up and running - should I try 4101?

I fired up Arcania earlier - the heatsink doesn't feel hot at all but my temps were showing closer to 70 - 75 C. Still seems too hot, fired up the first Witcher and even that was at ~75 C. I don't think there's any way I was running that hot when I played it.
Yup I cleaned off the previous compound (each time I reset the heatsink thinking that was the problem) and I use the pea in the middle as well.

My GPU and Mobo are both fine - it's just the CPU that was hot hot hot. Oddly enough it seems to have dropped a bit but I'm still concerned under load. It's idling in Windows at 40 C now which is where I was at before I think. And strangely it seems to be showing as running HOTTER when I'm in the BIOS menu (closer to 65 C).

It could also be that the new CPU require more wattage, thus increasing its base temperature. Check and compare the wattage's of your old and new CPU and let us know. For all we know, a somewhat higher temperature may be expected. Although, too high and it could be other issues.

- Tim

Okay I think I'm back in business.

After removing the heatsink for like the 8th time, it looked like one of the cheap plastic clear pegs had spread open a little bit too much. I THINK I was hearing the "click" from the black middle peg sliding down, but one of the clear pegs might have been outside the hole.

I went out of my way to squeeze the two clear pegs closer together and really make sure they were both in the hole... and my temps under load are much more respectable now. Computer is quieter too. I'm going to continue to monitor and will hold off closing this out for a day or so just in case.

It was funny, the thermal paste had barely spread out the last time too (the previous times it looked like it maybe wasn't spreading out "as much" - think penny sized - but I thought that was just me applying a bit less). It was a thick blob in the middle and a chunky clump on the heatsink. So I'm guessing I had really bad contact between the CPU and heat sink, despite pushing down on the heatsink / fan.

Let's hope it was just that one stupid peg - I hate the plastic pegs. In the last six months I've broken one and now this one almost cost me my CPU.

I usually wiggle the heatsink about 5-10° left and right for a couple of times while gently pressing down in order to make sure the thermal paste has spread evenly.

Having a good thermal paste can also make a lot of difference, so don't try to cut on costs in this department - it will only hurt your processor in the long run. Some thermal pastes also have a setting/curing cycle that you need to follow by getting the processor as hot as you can, then letting it cool for a few hours and then repeating the process for a couple of days - it should be described in your thermal paste usage guide if that's the case, anyway.

Think I'm all set. Might check one more time if I get overly paranoid / stupid just to make sure the paste spread out okay but I'm guessing I might have had a peg improperly seated. The trick was it didn't wiggle and sounded like it clicked when it went in.

So far, Arcania is running at closer to 55 - 60 C - MUCH more palatable and I think probably in line with what I can expect from a stock cooler. Plus, that sounds like pretty safe operating for a mid-tier game, right?

Time to bring on Witcher 3 without fear? I couldn't wait to grab it this sale, now I'm all worried I'm going to fry my CPU ;) But feeling a bit better now ;)

CPU have thermal throttling to prevent damage from overheating.