AMD Bulldozer X4 FX-4100 (95W)orAMD Phenom II X4 955 Black Edition (125W)
Providing that your motherboard can handle upto a 125W chip. I'd definitely go with the Phenom II X4 955 B.E. The Phenom II's out perform even some of the newest fx series. I considered the fx 4100 and the Phenom 960T for a short while, went with the 960T (still need to actually buy it) but I wont be regretting it. Phenom over FX series.
AMD Bulldozer X4 FX-4100 (95W)
I haven't looked at the 955, but I'm assuming that its very similar to the 965. The Zambezi chip is overall a much better CPU, but there's not as much support for it as the Phenom II's (motherboard wise). If you have an AM3+ board or an AM3 board that can have the bios updated to support AM3+, then by all means save yourself the $20 or so and get the Bulldozer. But if your using an AM3 motherboard that can't be updated to support it then your kinda stuck with the Phenom II. I just recently upgraded from a Phenom II dual-core to the 4100 and I love it, but either way your getting a great CPU. I don't know if I helped much but I told you what I can.
the phenom and here is why the bulldozer does not technically have 4 physical cores it shares resources with all the other ones. the phenom actually has 4 physical cores meaning when you use all four cores at the same time the phenom should still pretty much keep up with it but for single threading and non multitasking the phenom should technically beat the bulldozer and since hardly any if any programs are writtin to utilize multiple cores sing threading is still most popular right now. the phenom would work best. But i would go with whichever has the best deal at the time but in pure perfermance i would take the phenom. Unless power consuption and a very very tiny bit less heat is that big of a deal for you and the 30 watt difference if ran 24/7 probly would not come out to 3 dollars more a year but depends what you get charged.
The Bulldozer is the best choice, perhaps marginally, but if the other post was correct about the overclocking capability then that increases the potential benefits.
