Overclocking newb + crappy watercooler = PC that wont boot 3 times out of 4. I'll do a ram check but i think it might be time for something new:
Its a xeon x5650 which I've had running between 3300 and 3800Mhz. gtx970. 12gb fast (7-7-7-21) ram. I was trying to wait for haswell-E but I'm not going to make it. i found this site:
Which seems to suggest the skylake i7-6700 will at least keep up with the xeon, but have no idea if their benchmarks include the sort of workloads that video editing place on a system. Skylake at least will allow me to think about getting a couple of M2 SSDs. Currently editing 4k is painful - unless I resize it on the timeline (any zooms or reframing and I get nowhere near 25fps).
Single Xeon is not worth the money. Dual Xeon can be an option if you have very deep pockets. Skylake is around minimum for 4K material. The best way to go is Haswell-E, which has been around for several months.