Amount of memory I can get.

Hey everyone,

I remember awhile back someone saying that windows xp only recognizes up to 3.5 GB of memory. What if I have XP Pro (32 bit) will it make a difference. I was thinking of upgrading to these: http://www.newegg.com/Product/Prod [...] 6820145184 Seem to be a steal.

So here's the thing right. 32 bit operating systems can only use 4GB of memory. This is all inclusive... in other words this includes your video memory and a few other small things that will make your computer "see" less than 4GB of RAM installed.

What are you running now? If that is an upgrade from say 2GB or something then it will still be fine.

Go ahead and buy the RAM. You will see a slight boost in general multi-tasking. Most games won't benefit.

I'm guessing 32-bit Windows will recognize about 3.3GB of it.

As mentioned, 32-bit systems are limited to 4GB of addressing which includes the RAM, video card etc. It's not a Windows limitation it's a hardware limitation. A single line is ON or OFF (2 address locations) and 32 lines with all those ON/OFF combinations maxes out at 4GB of addressable space. Okay?

I noticed an obviously snappier overall experience when multitasking when going from 2GB to 4GB in Vista x64.

You might wish to get a copy of Windows 7 RC 64bit when it comes out on May 5th. it'll be good for probably 6 months to a year. This may help you decide to get an OEM copy when it's released. It'll be fun to try and it's free. You may wish to dual-boot. Either way, do a fresh install. Acronis Disk Director 10 is a great Partition Manager for adding a second hard drive partition or changing existing sizes. There are programs but I know this one works great.

Also, I didn't notice what your hard drive was. Your money might be better spent on a newer hard drive. Adding more RAM, or improving hard drive speeds will both speed up your system, but in slightly different ways. You can go to the hard drive manufacturers to find out the specs.

FYI about video cards:
A 1GB video card in a 32-bit system might drop your maximum possible RAM to 2.5GB. In SLI (two cards) the RAM is "cloned" for anti-aliasing etc but the actual system only "sees" 1GB, not 2GB.

It's not a Windows issue - it's a 32-bit issue. If you get 32-bit OS of any type, it will only be able to see/use 4GB of RAM (max). Windows sees a little less because of the way that it reserves address space for some hardware/devices.

It is because it is 2 to the 32nd power (just over 4GB of RAM).

Uh, no. huron and I have it basically covered.

I'm not going into the slightly more complicated involving extendable addressing etc. Basically it's a 2exp32 issue involving Windows allocating a small amount and the RAM, video, BIOS etc taking the rest.

But you go ahead and get 6GB of RAM working under XP 32-bit. I'll be impressed.

mikrev007 wrote
"a statement that the hardware was the limitation - which is not true (sure, it can be, but that would limit a 64bit OS as well). "

Yeah, 64-bit does a hardware limitation. Since available addressing doubles with every line added, 33-bit means 8GB and 34-bit is 16GB. No desktop computer is going to need 2exp64 of RAM.

Actually Microsoft just thought up some artificial maximum numbers for supporting RAM on various systems. I forget what they are.

32-bit XP is Not, I repeat, is not "crippled"; there's 4GB of total available addressing available and that's it. Windows will set aside a small portion for something we need not get into but the rest is for your video card, BIOS, other hardware and any System RAM up the 4GB total addressing limit if enough RAM is installed.

People seem to feel Windows is crippled by not using 4GB of RAM because they keep confusing the "Memory Map" (addressing space) to the physical System RAM.

PAE does not work at all, you need PAE supporting drivers and even when you do, it can be a buggy experience. That's why they disabled it in Vista. If i remember correctly PAE extends the address limit to 36bits. 64bit Windows OS's can only see up to 64TB of RAM, you can call that 'crippled' but XP is not, its just how addressing ALL the memory works (bios, cpu cache, ram, gpu ram, etc.)

mikrev007,
http://duartes.org/gustavo/blog/po [...] memory-map

Your video card (mainly your video RAM) would be in the "approx 1GB for PCI space" section. Windows and other software uses the large grey, roughly 3GB area.

I'm done trying to explain it. And I'm not going into PAE etc. Believe me or don't. Bye.

To add a bit: DEP was introduced in XP/SP2, but even before that there was a PAE kernel. Before SP2 there was support for 4GB system RAM. If 5GB address space was needed to address those 4GB, it was provided trhough PAE. They removed that in SP2.