i am looking at a few deals on oem cpus which have 'bk' in their serial numbers. i don't know about their performance, warranties, performance, longevity (especially with oc) etc. the cpus are -
core i5 2300, 2400, 2500 (non k) and i7 2600 (non k).
I have bought a couple of OEM AMD CPU's and two are still up and running after several years! CPU's are probably the most reliable hardware in your computer, either broken on delivery or they will last.