64-bit processors
 

I've heard that the opteron and the itanium 64-bit processors are quite different from each other. I know that linux is processor specific, so I was wondering since the itanium drifts from the standard x86 way of doing things, has linux been optimized for it? The reason I ask is that I'm going to be building a computer soon and putting linux on it and I want to know if I should get an Itanium or an Opteron. Any input is appreciated, thanks!

Jim

The Itanium and Opteron are pretty similar when it comes to running 64-bit code, except that the Opteron is considerably cheaper in terms of currency per BogoMIPS.

The major difference comes from running 32-bit code; the Opteron interprets it natively while the Itanium uses a 64-bit emulation of a 32-bit processor.

So long as all your Linux software is compiled for a 64-bit processor, you won't notice any difference, aside from your bank balance, to differentiate between the equivalent speeds of the two processors. If you're going to dual-boot a 32-bit OS as well (such as any Windows OS), or if you're going to run any binary-only software that hasn't been compiled with 64-bit instructions, then the 32-bit code will run considerably faster on an Opteron than an Itanium.

My advice would be to get an Opteron. However, the major reason for using a 64-bit processor is (in my opinion) to get around the inherent 4Gb memory limit of a 32-bit address; Linux can work around this quite well even with a 32-bit processor, so if cost is a major concern, you might even consider an Athlon or Duron.

Thanks a lot!! I'll look into the Opteron pricing! Does Gentoo utilize a 64-bit kernel?

I don't think you are going to be gettting an Itanium. The intel Itanium is first of all NOT x86 anything it is a completly new archtecture. Second of all it is not meant for home use at all, super computer stuff only. Also the price of Itanium processor alone is about what most people are willing to spend on a whole system (About $1200, and that's the cheap one).

If your building this computer for home use I would just get a socket 939 Athlon 64 3500+ and wait untill the end of this year when Athlon boards that support PCI-Express are out in abundance. By January the 3500+ should come down about 100-200 and the PCIE boards should also be cheaper and easier to find.

If your planning on going with a multi processors setup in your system then an Opteron is your only 64 bit choice. Your going to have to pay a bigger price when you buy those, everything for a "server" class product is more expensive. Depending on the Motherboard you get you may need a more expensive power supply and a larger case.

I am not planning to do a multi-processor computer, what makes Athlon 64 preferable over Opteron for home use?

Also, does anyone know if Gentoo Linux has a true 64-bit kernel, or if it just supports 64-bit processors?

Opterons were designed for server environments. Athlon 64 and Athlon FX were designed for desktop environments. The benchmarks shows this well even though the benchmark programs were run in Windows.

The Athlon 64 is prefered for home use because of the price. An Opteron is going to be more costly for chip, motherboard, powersupply, larger case, etc etc etc. The Opteron is really meant for 2-8 way processing. The Athlon 64 is the consumer version of an Opteron. The FX line of chips IMHO is a complete waste of money and aimed at the very high end niche market. The slight extra performance is hardly worth the price jump.