It's about time to upgrade my home pc / workstation, and I'm looking at one of the 64-bit Athlon FXs. If I do decide to go that route, I'd prefer to use a 64-bit version of Linux so that I can make the most of my CPU. Now, I know that Windows XP 64-bit can (or at least is supposed to be able to) run 32-bit apps when running with a 64-bit CPU, and that the FX series is capable of running 32-bit Operating Systems and software, but what I want to know is if I install a 64-bit version of Linux if I can run x86 apps, or if I'll be restricted to running only 64-bit binaries?

I have an Athlon64 3200+ (not FX, but the design for this discussion is practically identical). The binaries you will run will be designated "x86_64" instead of "i386", and these precompiled binaries are, in my experience, the only ones that will run. My uneducated opinion on the matter is that it's a limitation of RPM, not of the kernel.

The way to get around it is thus: either install a 32-bit OS (Fedora Core 2 i386 is running on my machine right now), or install the x86_64 version and then compile all 32-bit apps from scratch that you need. Depending on your needs, this may not be sufficient or satisfactory for you.

What specifically would you like to run? Are the apps too numerous to list, or is it a few that you could send out to the forum and let me/us test them?

Given tek1024's explanations, I would not go for a 64-bit CPU yet if I were the OP. The existing 32-bit CPU's are still plenty fast, and IMO, there will not be a very wide variety of (precompiled) 64-bit Linux applications available for the next couple of years.

It's true; if I were not already committed, I might not have gone 64-bit (though definitely AMD). It is a lot of work, but it's also quite rewarding if you're willing to put in the time and energy. Frankly, I was looking for something a little more quick and easy, but I don't plan on upgrading CPU/mobo for another couple of years. (With my Abit KV8-Pro, I'll be overclocking the beast as the next "upgrade.") It's up to you whether it's worth recompiling &c.

it also depends on what Linux you would want to be running. If you run a source distro like Gentoo there won't be a problem.

To tek1024: If it is an rpm matter, then it wouldn't be a problem on non-rpm based systems, like slackware. Somehow I find that strange...

I agree with elluva. If you're going to run a "non-standard" archetecture, I'd stay WELL away from any distribution that even WHISPERS ".rpm" or ".deb". (Don't get me wrong; there are some great binary distros out there.) I've been running Slackware for about 6 months and I ran Mandrake for about 6 months prior to that, and Red Hat before that. In my experience there's a lot more software available in source format than in binary format, and unless you get a "source-based" distribution, you'll run into a lot of trouble getting things to compile right (due to distribution-specific directory structures, config files, etc.).

Conclusion: Go get that rockin' processor and put a "source-based" distro on your computer. You'll be glad you did.

There's my two bits Have a good one.

--Dane

Yeah, I didn't think that it would be possible. At least not on the Linux side.

Maya, Shake, and MainActor are the only apps that I'm really concerned about, as they (obviously) won't release the source code, and no binaries have been compiled for 64-bit architecture. For those, and other items that I can't get in 64-bit flavor yet, I'll just have an install of an i386 distro, and then 64bit-something for everything else that I can compile or find x64 binaries for. Ah well, I've got no problem having 3 or 4 OS' installed.

Thanks for the tips, guys.

OK, ppl, this goes out from somebody that did an upgrade from an AMD K6-II @ 500 to an AMD Athlon 64 3200+. Me ... Anywayz... I had Linux x86 installed (Mandrake Linux), with a custom built kernel for my old CPU. After the upgrade, I booted that linux install. I was 95% sure it will fail somewhere along the road - the kernel was too "custom", let's say...

I was wrong, and it even booted up and loaded my nVidia module. The one thing that failed was a driver for a 1GB lan NIC, which was not compiled with the kernel... As for the rest, I made no reconfigurations... KDE starts up in 15-25 secs, and I'm also trying out the 64bit distro from Mandrake that brings KDE up in 4-6 secs. You do the maths... ;-)

i386 should be compatile with x86, so an x86_64 should have no prob. Try Mandrake, if all else fails. 32bit or no, it should work perfeclty on a 654bit Athlon