Re: i5 sandy bridge upgrade for a Q6600@3.45
The Sandy Bridge systems would be a significant upgrade over a Q6600. Whether it'd be worthwhile to spend $100 more on the I7-2600k than the I5-2500k, I can't say. It would probably depend on how much use you make of multithreaded applications.
Unfortunately, on 1/31 Intel announced a hardware problem with the 3Gb SATA controllers on the H67 and P67 chipsets that can lead to failure of the controller. (Intel claims a 5% probability within 3 years. The two 6Gb SATA ports are not affected.) There will be a recall on the SB boards sold to date. Some sellers have removed all of those boards from sale. (Newegg has removed the CPUs as well, although they are not defective.)
I just received my Asus P8P67 Pro today. I decided to use it, rather than wait 2-3 months. (Already had the CPU and RAM.)
Intel I7-3930k, Asus P9X79 Pro, nVidia GTX680, Asus PA246Q monitor, 4 X 4 GB g.skill DDR3-2133, Creative X-Fi Titanium, Corsair Force GT 120GB SSD, WD Caviar Black 1.5TB, Win7 X64 Pro