Anyone with Sandy (2500k/2600k) moving to the new Haswell-E chips? The 5820k is super tempting right now. And my 2600k is acting up, won't keep overclock at 4.5. Getting random lockups.
Ha, funny you bring this up... I JUST put together my new PC yesterday. I was coming from a 2500k, upgraded to a 5820k.
The 2500k will still give you good performance in games, no doubt. The reason I upgraded was that my CPU, like yours, was being a bit flaky at times. I also wanted a more modern feature set on my motherboard, and I wanted to create a silent PC which required replacing the case and fans anyway.
Overall so far, I LOVE my 5820k. It's overclocked to 4.2GHz, and with my H110 cooler it stays below 70 degrees Celcius even running Prime95. And that's in a silent case! You put these parts in a HAF X, it'd be around 60C. (I know this because when I took off the panels hiding the fans, it dropped down to 60.
I game on my PC, but I also encode videos every now and then, and I'm using it for school which has me running a lot of VM's for class work. This processor handles them so much better, I couldn't be happier with my purchase.