Just how much RAM can x86 XP read?

Skeeter · 8 Feb 2008 at 15:39

Hi

Now, I was always under the impression that XP couldnt read 4GB of RAM, because it just cant with 32bit addresses, and was told about 3.5 total would be my limit.

Thing is, Ive got 4x1GB sticks of PC2-6400 in my machine, allong with a 512MB 8800GT. According to logic, people, experience and a mates identical setup I should be getting around 3GB - 3.25GB of available RAM in Windows. But I have 3.5. Including the 512 on the GT this ia a full 4GB?

Its not a glitch in My computer properties, as when I ran the Valve hardware survey yesterday it showed 512MB on graphics, and over 3500MB as RAM.

Why could other people be loosing another 250-500MB RAM compaired to me on an identical setup?

tntcoder · 8 Feb 2008 at 15:41

3449679872 bytes / 3.21 gb, thats max for 32bit addressing i think.

.walls · 8 Feb 2008 at 16:01

A 32 bit computer can address 2^32 = 4,294,967,296 bytes of memory, or 4 gibibytes (GiB).

This includes system memory, gfx card memory and the various ROMs and other memory (HBAs for example) in the system.

NathanE · 8 Feb 2008 at 16:04

It can address 4GB. But the graphics card and other hardware memory maps can eat into that virtual memory address space a lot which reduces the amount of potential physical memory that can be mapped.

bledd · 8 Feb 2008 at 16:09

god, make a sticky called :Autologin, 4gb XP

.walls · 8 Feb 2008 at 16:20

bledd. said:
god, make a sticky called :Autologin, 4gb XP, Best AV

Fixed...

bledd · 8 Feb 2008 at 16:22

nah we need one of them not in the sticky or Windows forum would cease to exist

.walls · 8 Feb 2008 at 16:27

true... but maybe we'd get some questions that haven't been asked 400 times before... just maybe, though...

OzZie · 8 Feb 2008 at 16:35

For some people, Windows sees 3.5GB and others slightly less.

Not seen any x86 system use more than this though.

Burnsy2023 · 8 Feb 2008 at 17:23

bledd. said:
nah we need one of them not in the sticky or Windows forum would cease to exist

Dude, have you learnt nothing? As sson as you make a sticky it's an unwritten law that you can never read it, even if it does answer all of your questions. Proper proceedure is to post endless threads on the same topic :rolleyes:

Burnsy

Skeeter · 8 Feb 2008 at 21:53

Im well aware of the limitations on XP addressing anymore than 4GB, so shutup with the 'same question 400 times' trolling and move on.

My question, if you bothered to read my post is why Im able to see 3.5GB of physical memory, and have 512MB for graphics, when other people can only see 3 or 3.2GB of physical memory!

jak731 · 8 Feb 2008 at 21:57

Skeeter said:
Im well aware of the limitations on XP addressing anymore than 4GB, so shutup with the 'same question 400 times' trolling and move on.

My question, if you bothered to read my post is why Im able to see 3.5GB of physical memory, and have 512MB for graphics, when other people can only see 3 or 3.2GB of physical memory!

basicly, they have graphic cards that have more memory on then such as the 8800GTX that has 768MB or 3870 that has 1GB

Fire Wizard · 8 Feb 2008 at 21:59

It is all dependent on your hardware configuration and that's why it varies from one machine to the next.

Skeeter · 8 Feb 2008 at 22:02

jak731 said:
basicly, they have graphic cards that have more memory on then such as the 8800GTX that has 768MB or 3870 that has 1GB

Skeeter said:
Why could other people be loosing another 250-500MB RAM compaired to me on an identical setup?

The ability to read, it helps

jak731 · 8 Feb 2008 at 22:05

Skeeter said:
The ability to read, it helps

i did quickly, then forgot the context of your opening post

.walls · 9 Feb 2008 at 00:04

Skeeter said:
The ability to read, it helps

lol... because you read my post properly, I'm sure

I doubt very much if the setups are "identical". Try google if you think i'm trolling - this sort of question has been answered countless times on this and many other forums - all you have to do is read

Burnsy2023 · 9 Feb 2008 at 00:46

Skeeter said:
Im well aware of the limitations on XP addressing anymore than 4GB, so shutup with the 'same question 400 times' trolling and move on.

Just for the record, my comment wasn't directed at you, it was a general statement

Burnsy

Skeeter · 9 Feb 2008 at 01:18

My PC: DS3, 8800GT, E6400, 4GB Corsair RAM - I have 3.5GB in XP

Mates PC: DS3, 8800GT, E4500, 4GB OCZ RAM - 3.2GB in XP, which dropped to 3GB when he added an XFi?

Im not complaining, as I seem to have the better end of the deal here. Im just highly confused, as the actual ammount of RAM you get appears to be more random than science!