Ramming Speed! Or ramming systems anyway.
January 3, 2008 4:41 PM   Subscribe

I've got 32bit windows XP. I also have 8 gigs of Ram. The windows specs say it'll only recognize 4 gigs. Other than converting to windows vista, is there any way to get my machine to recognize and use the other four gigs of ram?
posted by rileyray3000 to Computers & Internet (17 answers total)
32bit computers can only address 4gigs of RAM. Move to 64-bit hardware and a 64-bit OS if you need more. Its worth mentioning to enable PAE in 32-bit windows to get that full 4 gigs.
posted by damn dirty ape at 4:46 PM on January 3, 2008

To put it simply, no. 32 bit mode on an x86 can only has 4 gigs of total address space, and I think a gig is taken up for device DMA, so you really only have 3 gigs of real memory. Gotta upgrade to 64bit to get access to that memory.
posted by hamhed at 4:47 PM on January 3, 2008

Read all about it here.
posted by damn dirty ape at 4:47 PM on January 3, 2008

yes, if you use Windows XP 64-bit. You could also use Linux.

Unless you're compiling the application yourself, or you find a 64-bit windows program, you're not going to use those extra 4 gigs. It's not a Windows issue, it's a law-of-computer-science issue. your computer will address 2^32 bits of space, which tops out at 4 gigs.

My suggestion would be to switch to vista (if you don't want linux). I've read that XP 64-bit is a real pain, and that it's difficult to find drivers for.
posted by unexpected at 4:47 PM on January 3, 2008

rileyray3000 you have not provided enough information to answer this question. in order to address more than 2^32 bits of ram (4GB) you will need to have a 64-bit processor. if you have a 64-bit processor you can install a 64 bit version of linux or windows, if not you are out of luck.
posted by phil at 5:01 PM on January 3, 2008

No. Your computer refers to locations in RAM by specifying a number in binary. Due to the way computer systems are designed, all these numbers must be the same number of digits long (including, possibly, some 0's at the beginning). The "32" in "32-bit Windows XP" is the number of digits. If there are more bytes in RAM than the largest 32-digit binary number — 11111111111111111111111111111111, or 4,294,967,295 in decimal — there are some bytes you can't reach. You can't say, hey, I want byte #5,000,00,000, because there's no way to write that as a 32-digit number.
posted by panic at 5:13 PM on January 3, 2008

I concur with the above taht you'll need a 64bit OS to see more than 4 gigs (really, more than 3Gb), but disagree that XP64 is a bitch. I had to fiddle a bit, but was able to install XP64 just this past weekend on my latest system. XP64 allows most of your 32bit programs to run in a 32bit emulation mode, and even my two year old motherboard's drivers came in XP64 flavor.
posted by notsnot at 5:36 PM on January 3, 2008

I've tried WinXP 64-bit, but it ran so poorly, crashes so often, and you couldn't get drivers for even simple things, like a skype phone or scanner.

I would suggest you do this:
1) Install Linux 64bit as your base OS
2) Run Windows XP on top of Linux using VMware

You can still only get ~3gb of RAM for the WinXP VM, but now you can run a few instances of VMware and make use of that RAM rather than wasting it.

posted by bumper314 at 5:54 PM on January 3, 2008

1) Not with 32 bit windows, you need a 64bit os.
2) Windows 64 bit is different from Windows x64, you want the x64 version. The 64 bit version does software emulation of 32 bit applications. The x64 version uses hardware emulation for 32 bit applications.

With Windows x64 some applications will just refuse to work, saying they are not targeted for that platform. Most things work fine though, and a lot of companies include Windows x64 drivers for hardware.

Oh, and you need a 64bit processor.
posted by Sonic_Molson at 5:55 PM on January 3, 2008 [1 favorite]

Also be aware that Vista comes in both 32 bit and 64 bit versions, so you wouldn't just need "Vista", you would need "Vista 64 Bit Edition". When downloading drivers and stuff, you will want to look for things labeled "x86-64" or "x64". Things that say just "x86" are compiled for 32 bit hardware, so don't get confused.
posted by tracert at 6:03 PM on January 3, 2008

Yes, you can use XP 64-bit, aka X64. However, there are (yes, still) lots of missing drivers, or drivers that just plain suck. Some major culprits are wireless adapters, printers, and specialized hardware. Also I found that video card drivers (in general, and ATI in particular) are behind their 32bit counterparts. Oh, and software firewalls and virus scanners need to be 64bit specific, which some companies don't make (and others only license under their business class license). Anyway, I don't recommend it.
posted by anaelith at 6:14 PM on January 3, 2008

Yes, you can use XP 64-bit, aka X64.

These are 2 different operating systems, as I mentioned above.
posted by Sonic_Molson at 7:06 PM on January 3, 2008

Sonic_Molson, I'm confused. Are you talking about the software made for the old Itaniums? I've never heard anyone differentiate between the two before, since it's pretty hard to accidentally purchase an Itanium, and since that OS hasn't been supported since the middle of 2005 anyway.... Even Microsoft seems to have succumbed to the lure of simplified naming, that is, if you believe search results.
posted by anaelith at 9:59 PM on January 3, 2008

While it is true that Windows XP does not support more than 4 GB of physical memory it is not true that you need a 64-bit OS nor do you need a 64-bit processor to support more than 4 GB of memory. A 32-bit processor can only directly access 4 GB of memory at one time, but through a windowing or bank selection mechanism you can access more than 4 GB. For example the 32-bit version of Windows Server supports up to 64 GB of physical memory running on a regular old 32-bit Pentium. The hardware support is provided by Physical Address Extension (PAE) and the software support by Address Windowing Extension (AWE). Computer systems from the earliest days have had similar mechanisms for accessing more memory than the physical address space of the CPU.
posted by JackFlash at 10:37 PM on January 3, 2008 [1 favorite]

In Windows XP from Service Pack 2 onwards, the PAE switch does not do anything. Driver compatibility problems proved to be so intractable that Microsoft basically just turned the option off forever.

(JackFlash wasn't recommending you try PAE on XP, but sooner or later someone will. :-)

I wrote a piece about the "3Gb barrier" (4Gb address space minus MMIO memory holes equals three point something gigabytes of usable RAM) a while ago. It makes this whole issue about as simple as it can be made, which is to say, not very.
posted by dansdata at 12:34 AM on January 4, 2008

JackFlash is right about PAE, but there are other performance penalties that go with it that haven't been mentioned yet. The bank switching is pretty computationally expensive, so overall speed benefits are not guaranteed, plus you still face other hard limits. If I remember correctly, 32-bit Windows with PAE enabled can still only allocate 2 GB per process, so no single program gets to romp through a 3, 4 or 7 gigabyte meadow of RAM no matter how much is installed in that scenario. (one quirk about this is that 32-bit windows apps do get up to 4 gigs of space when run under 64-bit windows. odd.)

A friend has an 8 GB 32-bit windows system with an unusual configuration: 4 GB system RAM (utilized normally) with a forced/defined 4 GB "swap" that actually lives in the remaining 4 GB or RAM (a ramdisk swap drive, to put it another way). That may require specialized hardware (like a special PCI Express card), but I'm not sure.
posted by NortonDC at 4:53 PM on January 4, 2008

anaelith, yes, the software that was used for the Itaniums. I was able to download a copy through MSDNAA and it worked fine on an Opteron, apart from all 32-bit applications being painfully slow. You're right that the OS has been dropped by Microsoft, I was just pointing out the differences so the OP doesn't get stuck with the wrong OS.
posted by Sonic_Molson at 8:52 PM on January 5, 2008

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