5
votes

Is windows XP 64-bit still available to purchase? I want the 64-bit version so I can use 8 GB of RAM.

1
  • XP 64bit is really bad.. I would choose Win7... May 16, 2009 at 19:37

4 Answers 4

10
votes

Yes, sort of. You can run XP Professional by buying Vista Business or Vista Ultimate and exercising your downgrade rights (you have to find an original XP installation medium then call Microsoft to obtain a product key.)

You might be able to find Windows XP Home (OEM version, which you cannot legally install on a pre-existing computer) if one of the shops in your area still carries it, but that's a pot shot.

However, you cannot use 8 GB of RAM with a 32-bit operating system (except on Windows Server 2003 through the cumbersome PAE mechanism, through which any one app can use up to 4 GB of RAM if it supports the special AWE API.) Actually, you will only be able to use about 3.5 GB. You need a 64-bit operating system for more than that.


Edit: You updated the question to mention 64-bit. Like Michael Stum pointed out, 64-bit XP is a nightmare to maintain due to very poor driver support. There's only the Professional family, there never was a 64-bit XP Home. However 64-bit XP is subject to the exact same life cycle policy as the 32-bit client operating system (see Windows XP Professional x64 Edition Service Pack 2 life cycle on the Lifecycle Information for Windows Client Products site for details). In other words, it is no longer available through retail channels, and though I've heard rumors of OEM versions I've never actually seen one offered on sale, only bundled with systems through big OEMs.

According to Microsoft's downgrade rights chart (Warning: Link to a Microsoft Word document!) says you can downgrade to 64-bit XP if you find an original installation medium somewhere:

Can I downgrade my OEM version of Windows Vista Business to Windows XP Professional?

Yes. OEM downgrade rights for desktop PC operating systems apply to Windows Vista Business and Windows Vista Ultimate as stated in the License Terms. Please note, OEM downgrade versions of Windows Vista Business and Windows Vista Ultimate are limited to Windows XP Professional (including Windows XP Tablet PC Edition and Windows XP x64 Edition).

(emphasis mine)


Further edit: Funny how the world works. Just came across (via reddit) this very interesting page regarding 32-bit and >4GB in Microsoft operating systems: Licensed Memory in Windows Vista

4
  • Note that PAE isn't supported in Windows XP at all, and even in the Systems that support PAE (Win2003), only applications specifically coded can make use of IT. May 16, 2009 at 16:29
  • Thanks, Michael, edited post to outline that PAE for >4GB is only possible on 2003. May 16, 2009 at 16:33
  • 2
    Not quite right: PAE is supported in XP, however, AWE may not be. What this means is that with PAE turned on, the kernel may be able to access more than 4 gig of memory, but the applications can't break the normal 2 or 3 gig limit. The kernel is able to use that extra memory for pretty much anything. (Reference: Windows Internals, Fourth Edition, section on PAE and section on AWE. They don't say which windows version support AWE, but they do say that XP supports PAE). May 16, 2009 at 17:07
  • Now that's indeed interesting. Just looked and yes, /PAE is indeed supported on Windows XP. My fault, was confusing PAE and AWE apparently. May 16, 2009 at 17:12
2
votes

Just a thought, the other posters have mentioned the perils of 64-bit XP, particularly from the drivers standpoint -- if you're just looking for XP rather than a server OS, why not download and install the Windows 7 RC? It will be good until June 2010, though nagging will start in March. It's likely pretty close to what the final release will look like, and there's a virtualized XP compatability mode. Obviously, it's still beta software, so YMMV as they say, but it's already a clear improvement over Vista with respect to drivers and UAC in particular, and again it should be pretty close to what the final Win 7 release looks like later this year.

1
vote

The 32-bit version can not access more than 4GB of RAM. The 64-bit version has a 128GB limit.

Vista 32-bit has the same limitations. Except 64-bit Home editions have a lower maximum (16GB and 8GB respectively for Premium and Basic)

See http://msdn.microsoft.com/en-us/library/aa366778.aspx for all the different limits.

The 64-bit version of Windows XP is still listed as for sale on sites such as NewEgg.com, Amazon, there's always eBay and other sources. So yes it's still available for sale and the downgrade rights which both Vista and Windows 7 provide allow you to obtain a license key from Microsoft if you can provide the install media.

1
  • Actually, according to the table in the "Past" section of geoffchappell.com/viewer.htm?doc=notes/windows/license/…, that limit doesn't apply to all versions of XP: Enterprise allowed 32GB and Datacenter allowed 16 or 64 GB, depending on whether or not you used "4 Gibabyte Tuning".
    – SamB
    May 3, 2011 at 18:59
0
votes

You updated your question to say XP 64-Bit. It escapes me why anyone would want this (It's not really WinXP, it's an XP/Win2003 Hybrid with really bad drivers and application support, or as I'd like to call it, it's the Windows ME of 64-Bit Operating Systems), but it still seems to be available, at least in Germany and other European countries I still see the SystemBuilder Version normally available with no sign of End-Of-Life.

1
  • I don't agree. XP 64, thanks to being based on 2003, is much more stable than XP 32. I'm using it on two desktops and laptop and only thing with driver problems is finger reader (probably because I don't have enough motivation to look for it). 32 bit applications work without any problems, except some firewalls and antivirus, but you can find native 64 bit equivalents.
    – TJL
    May 22, 2009 at 8:27

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