32-bit Computing With a 64-bit processor

I’m still trying to put together my new computer, though I probably won’t buy any time soon. Anyway, I’ve thought about going to one of AMD’s 64-bit processors. Will I need to get WinXP-64, or will my 32-bit copy of XP Pro work? How about my 32- and 16-bit applications? Am I entirely missing the point of 64-bit processing if I don’t go immediately to XP-64 (that’s another couple hundred bucks I’d rather spend on hardware if possible)?

The (main) point of 64-bit processing is that the processor can address 17,592,186,044,416 megabytes of memory, instead of the 4,096 megabytes that a 32-bit machine can address.

This is useful when you’re dealing with computers that need lots and lots of memory–large databases, simulations, etc. For your average desktop user, I don’t see much of an advantage. If I were building a machine for myself, I’d save my money and go 32-bit.

Your 32 bit windows XP environment will work fine, as will all your 32 bit apps.

You won’t however, be taking advantage of the 64 bit architecture. Which is why if you do build your own machine, I suggest you shop around (go to computer fairs and look for bargains), and if you find a faster 32 bit processor for less, then I’d say go for it. By the time 64 bit computing software support makes a 64 bit chip worth-while it’ll be time for an upgrade anyway.

I wouldn’t say that’s the only main point of 64-bit processing. Another benefit, if I remember correctly, is that a single 64-bit instruction can encode multiple simple CPU instructions. This kicks up the speed when used with 32-bit applications

So I would be better off taking the money I would have spent on the CPU and putting it into RAM?

Depends on what you’re going to use it for. Word processing? Quicken? Internet browsing? Assuming you already have 512mb of RAM, I’d look at adding a second hard disk and setting them up in a RAID 0 configuration.

Games? Dump the extra money into the video card.

The Tech Report recently did a big overview of 64 bit computing. I reccomend you read the article, as it should cover a lot of your questions. One thing to note is, that besides increasing the amount of memory that can be addressed, the x86-64 design has twice as many registers as the register starved x86 specs has - this greatly increases performance in many areas.

And right now, the 64 bit processors are not that expensive. Checking Newegg, the Socket 754 Athlon 64’s 2800+ are down to $120, the 3000+ $150 (I have the 2800+ chip, works great in everything I do) - compare that to the $160 2.8ghz Pentium 4. And the Athlon XP chips are getting harder to find; the Athlon XP 2800+ cost $100 on newegg, so why not spend the extra $20. (Especially since the Athlon 64 will be considerably faster in most 32 bit code as well.) Toss in a $80 Nforce 3 250GB motherboard, and you have a nice combo.
Or if you plan to go the PCI-Express route, a Nforce 4 board will cost about $100, and the Socket 939 Athlon 64 3000+ cost $150 or so. The 3.0ghz Pentium 4 is $180.

I should also note that for $515 you could have the heart of a powerful, blanaced computer - $87.50 Chaintech Nforce 4 motherboard, $185 XFX Geforce 6600GT video card, $97 Corsair Value Select RAM, 512 MBx2 (1GB total), and an $146 Athlon 64 3000+.

Just add a case, hard drive, optical drive(s) and software, and you are ready to go.

But only if the application was compiled to run on that specific platform by a compiler that can use those registers.

A version of Windows XP (the OP is using Windows, not a Linux distro) that can take advantage of the additional instruction set isn’t yet on the shelves, much less drivers and applications, and when it does become available, you’ll need to buy the new version or an upgrade and re-install the OS.

The price-based arguments are sound. If it isn’t that much more to upgrade to x86-64, you may as well do it. It won’t hurt 32-bit performance, and you’ll be able to upgrade your OS and applications at a later date if you choose to do so.

As already noted, there are other reasons to embrace 64 bit, but this one is liable to be the eventual catalyst for the non-gaming home user, as applications continue to increase their memory requirements, and more home users get into application areas such as video editing, which can benefit from the extra memory. 64 bit will eventually become a requirement, though many people probably could go through another 32 bit machine before being seriously impacted. Gamers are on a shorter horizon. Even non-gamers should probably consider a 64 bit machine if they intend to keep it for a while.

You should also note that the current crop of 64 bit motherboards mostly support a maximum of 4 gigs ram, at least the socket 939 AMD ones I’ve been looking at. Windows 64 bit OS’s will allow virtual memory far beyond the 4 gig barrier. Future motherboards will probably start allowing more actual memory.

      • WinXP-64 is at least 8-12 months or so off, last I heard. The beta that MS had on their site for free download seems to be gone* and it was an expiring copy anyway. I built my current Athlon-64 computer and everything installs just like normal, running a 32-bit OS and applications on an Athlon-64 doesn’t cause any more problems than a 32-bit CPU, that I have seen or read anywhere online.

*(my Athlon-64 motherboard came with a “free beta” of WinXP 64, which was just the webaite address where you could download the beta version. That link is dead, but it may still exist on MS’s site somewhere, -but since everybody already knew it was an expiring copy anyway, I never bothered looking)

Try following from here:


They’ve just closed the window for downloading an evaluation of release candidate 2. Another preview available “soon”.

Thanks to everyone. About every three months, I put a possible computer together (I’m going to cannabilize the old one for parts) with a specific new case in mind, but never actually buy anything. Then, of course, technology keeps going and prices change and something new is out. Since it might be as much as another year before I really get around to doing this, I might wait for WinXP-64 to launch and do it then and get a 64-bit processor.

Keep in mind that even if the OS is 64 bit, the applications won’t necessarily be. You might want to wait until WinXP-64 is launched and an application that you use (a game or something) is released specifically for that platform.

That would have been 6-10 months ago, right? There was me thinking it was only a month or so away. MS are up to RC2 or so.

See http://www.theinquirer.net/?article=21760

You sure about that? If they’ve got 4 memory slots, they’ll usually support 8 GB - but the 2 GB DIMMs are very expensive.

According to the specs on most of them, not:


ASUS A8N-SLI: “4 x 184-pin DIMM Sockets support max. 4GB”
Gigabyte GA-K8NXP-9: “Max capacity: Up to 4GB by 4 DIMM slots”
MSI K8N Neo2 Platinum: “Supports a maximum memory size up to 4GB without ECC”

First three I looked at off that page.

It might be that they will actually recognize and support the 2 GB DIMMs, but the published specs don’t reflect that.

For the money the althon 64 is a great chip. For a compareable P4 it is faster and less expensive (generally). The fact that it is a 64 bit chip and everything else is 32 bit is kinda beside the point, its still damn fast. Unless you’re totally penny pinching there is no good arguement to not get an athlon 64.

I’d say get another 512 MB. You can’t have too much RAM.

Sure, but there can be a point of diminishing returns.

I am surprised that people suggest settling for 512MB of RAM. I have found that I can easily run my commit charge up to 700+MB by opening a few applications… photoshop, outlook, homesite, IE, an antivirus, a firewall, and a game. And why would a home user want RAID 0? Better to buy the extra ram to avoid paging out to the hard disk at all, and get the faster disk if possible.

You shouldn’t really give guidance without knowing the user’s requirements. That’s rule 1 of helping people with this kind of stuff.