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).
They have a shorter warranty (30days) no cooling device but should be just as good as their boxed counterparts!
A none K Intel SB CPU will have very little overclocking headroom if any!