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I'm eyeing processors for an upgrade sometime in the next few months, and am thinking for going AMD over Intel for the first time. I've heard good things about AMD's phenoms... I'm thinking about the CPU linked above.

What I plan to run on it:

32bit edition Ubuntu, latest version.

Anyone have good/bad experience with this CPU? Will I be throwing out performance by using a 32bit OS? Anyone have any better recommendations for performance/$, in that approximate price range? What about Quad core vs. dual core?

FYI, it'll probably be beginning of December by the time I actually purchase- should I be looking for something new?

Phenom is ok now that the TLB bug has been fixed. $195 shipped is also pretty decent, the closest price competitor from Intel is the Q6600 so it is a toss up to which you would prefer. The original Phenom launch was a disaster, and even under optimal conditions is usually not as fast as a Core 2 quad at the same clock speed. It really would have been a lot better for AMD if they could have avoided the TLB bug and shipped Phenom in volume around the same time the Core 2 came out, because it stacks up well against the early Core 2 Duo/Quad processors. But thanks to all the trouble the prices for them are rock bottom.

64 bit software opens up more register space so in theory it is faster than 32 bit software... emphases on in theory... In reality there is virtually no difference. However the 4 GB address space limitation of 32 bit software remains. Although I'm not sure how linux manages it, but odds are you probably shouldn't bother with more than 4 GB of memory.

Krom wrote:64 bit software opens up more register space so in theory it is faster than 32 bit software...

x86-64 may be faster because the extensions make use of more registers. But registers aren't a single piece of "space".

At the end of the day, for most software you are not going to notice a significant difference between 64-bit and 32-bit versions of most programs. Unless they are programs that would benefit from 64-bit, mostly programs that work with larger numbers and larger amounts of data.

With a PAE-enabled 32-bit kernel, you have a 36-bit physical address space (64gb), but you're still going to be limited to a 32-bit virtual address space, which leaves ~3gb of allocatable memory per process.

I think the better question to be asking is why not run a 64-bit operating system? Flash and Java browser plugins used to be the tricky things to get working, but now there is nspluginwrapper to wrap the 32-bit plugin api over the 64-bit plugin api, which works for getting Flash to run on a 64-bit browser, and the iced tea plugin for Java is natively compiled for 64-bit, which works rather nicely as well.