Cooler seems fine. Not too loud. I get more noise from my case's intake fan. Relatively easy to install. Seems a no-brainer for the price.
My CPU is generally in the 1.2-1.3 range for voltage and doesn't get any hotter than 60C according to HWMonitor and idles right around 30C. I tried knocking the voltage down, but it didn't like it. I figure as long as temps are okay, it should be fine. OC-ing took some fiddling, but it will depend on your motherboard and BIOS options. As long as you take things slowly and deliberately, and you find the right guides and software tools, all should be well. If you haven't done it before, the basic concept for overclocking is to eke out more speed while keeping voltage as low as possible (in order to keep temps low). Be ready to reset your BIOS using the jumpers on your motherboard. A lot of trial and error and testing.
The big difference between the 2500K and the 3570K is that the old 2500 seemed to take whatever you threw at it. The 3570K seems a bit finickier. But just be patient. As I said, I gave up at around 4.3Ghz. I could squeeze more I'm sure, but it was getting a lot harder to find stable settings at 4.4/4.5. And these things also depend on other things too (your PSU, your case temps, your heatsink contact, the idiosyncrasies of your CPU, etc). Since I got reliable and safe results from 4.3, I just left it there. All told, it took maybe 3-4 hours of troubleshooting/testing/tweaking.
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