TLDR- i52500k permanent vs Phenom II 965 (AM3+ socket) with a future upgrade to processor line following or even later than BD.
I'm doing a build in early December and my biggest concern at the moment is the processor I'm going to use. From what I've seen, the Bulldozer series of processor suck extra large eggs, and I have since ruled them out of a possible build. However, seeing the excellent performance of the i52500k in benchmarks as well as real world performance (I will be using this PC for gaming), it seems like choosing the i52500k is a no-brainer. My only gripe with the i52500k is, as far as I can see, a relatively limited future upgrade path. As far as being a fanboy goes, I don't really have a clear preference as this is my first build, however I have been eyeing the AMD's more than the intel's and have seen that because of the excellent performance of the 990x motherboards and the nice backwards-compatability of AM3+ I could instead just use a cheap-ish 990x motherboard, slap in a Phenom II 965 and wait till AMD comes out with a good processor (I would be using one comparable in price to a 2500k).
I believe Piledriver will be AMD's final AM3+ CPU as they will be focusing more of their resources to the APU design. Llano seems to be pretty successful in the fact that demand actually outstrips production. I have not researched any numbers, so it could be than only 100 Llano APUs are being produced every month and only 120 Llano APUs are in demand every month. Or only 20,000 Llano APUs are produced, per month, but 40,000 are in demand. As most people in THG knows, the biggest shortcoming of Llano is the slightly weak Athlon II CPU core.
Financially speaking, dropping the CPU in the consumer market makes sense because it cuts down on R&D expenses. Continual research and development for consumer CPUs, server CPUs and APUs can be quite expensive. Not to mention complex since you are basically developing 3 different products. Production wise, cutting out the consumer CPU means fewer production lines to manufacture products to get to the end market. AMD does not have deep pockets like Intel and AMD must spend wisely on R&D because the compete in both the CPU (APU) market and graphics card market.
Intel's Sandy Bridge Core i CPU series basically provides 20% better performance than thier Phenom II and Bulldozer counterparts. The release Intel's upcoming Ivy Bridge will be the last series of socket 1155 CPUs and they will probably be 6% better than Sandy Bridge. Others might say 10% faster, but the CPU architecture is pretty mature and nearly all efforts to increase CPU performance will be devoted to Intel's next CPU generation; Haswell.
By the time Ivy Bridge comes out it will basically be about 26% faster than Phenom II and Bulldozer. Early estimates for PileDriver is that it will be 10% faster than the Phemom II / Bulldozer. That basically means Ivy Bridge is expected to be around 16% faster than PileDriver. Sandy Bridge would still be around 10% faster than PileDriver.
Wow, that was really informative, seems like this is a sucky time to build but hey, the 2500k is the best cpu for the money at the moment and since ivybridge wont be that much better I think my choice is clear.
There will be discrete desktop CPUs after the Piledriver based CPUs but they will likely use a different socket than AM3+. There should be a steady stream of new AM3+ socket CPUs for the next ~2 years IMO.
APUs will likely eventually fill all mainstream desktop apps except high end which will continue with discrete CPU/GPUs.