Athlon 64 floating-point performance gain?
 

As part of my university studies, I've written (in C, on Linux) a bunch of floating-point number-crunching code. Getting this code to run faster would be useful.

Right now I'm running it on an Athlon XP 2400. However, in the near future I've got the opportunity to get a new computer (family member wants a laptop, and since she doesn't do CPU-intensive stuff, she's proposed that I get the new one and give her this one.)

I'm looking at, among other things, the eMachines 68xx line, with Athlon 64 3000/3200 processors. I'm assuming this is a faster processor in 32-bit land as well, but would I see any drastic performance gain in my FP number-munching by getting a 64-bit distro and running my code under that on the Athlon 64?

If my code will benefit greatly from 64-bitness, that's a big mark in favor of the eM 6805/6809.

Related question: what's the floating-point performance on the Pentium-M's? I know they get obscene battery life, which is important to me... but I also want a computer that can do floating-point math at least as well as the Athlon XP 2400.

There are a few keys to get very fast floating point cruching such as memory speed, memory bandwidth, processor cache, and FPU efficiency. The processor in eMachines will not give you performance that you need. The specs in the eMachines 68xx is very poor for floating point applications because the memory speed is 400 MHz, 64 bit memory bus, and memory cache is 512 KB. You should look at systems that have FX-51, FX-53, or Opteron. These processors will give you the floating point crunching that you need. Their specs are 400 MHz memory, 128 bit memory bus, and 1 MB processor cache.

You should build the computer because buying a system from a computer manufacture like eMachines you will waste money with pre-installed Windows software. Monarch Computer can help build the computer. Monarch Computer uses parts from popular brands, so every component in this system is not taking away your performance.

If you really have the cash, you can get a dual G5 system or Itanium 2 system. Both of these will give you floating pointing speed.

BTW, this thread should in General.