I know any 32 bit operating system can only take up to 3GBs of RAM. I had Vista before with only 2GBs of RAM. It ran good enough. But I decided to go back to XP. But I want to upgrade 3GBs of RAM this time try again. Question is how much in exact numbers of RAM can a 32 bit system handle? 3.5?3.0? Or if anyone has more speicifics it would greatly apreicated.

Well first off, any 32 bit OS can take register a TOTAL of 4gb of memory. That includes ALL memory. Bios chips, DDR2, sound card, i believe even video memory counts. thats why everyone who has a 32 bit OS and 4gb of ddr2 memory installed has differnt results, becouse there system has memory in different areas ie sound card and stuff
 
Im sorry i could explain things very well its kind of confusing but i hope this clears things up for you.

Suicide is right.  There's no magical number we can prescribe you, however, many typical see ~3.2GB of RAM...you may see more or less depending what  components you have and what memory addresses they're using.

OP - Unless you are running a Crossfire or SLI system, you should be OK at 3GB.  It's going to become a little harder to pin down, though: Vista 32 SP1 will display the total installed RAM.  This is a Display Change Only - Microsoft did not re~engineer the addressing capabilities of the OS.

Microsoft doesn't need to re-engineer anything, if they wanted to support >4GB. The PAE kernel is already present in the system, they just crippled it, because they need it to support DEP.

Ah, yes...  the Great "Microsoft Doesn't Want Us To...." argument.
 
 
Meh

yes, but it is true

i am using amd x2 5600+; 2GB ram in dual channel, 512 MB 9600 and m using vista 32 sp1.
i was lookin towards updatin 2 4GB ram....but i wan dem 2 be in dual channel.
so if i install total of 4GB, wat amount will windows b abl 2 use.
if i install 3GB instead...will da rams remain in dual channel??

 
As some of the others said, you can't really be sure of the exact amount but it's usually .5-.8gb depending on your hardware.  With the price of DDR2 800 RAM these days I think you're best off  just going to 4GB and deal with the .5-.8gb you'll lose.
 

 
Let's see if I can tackle this one with a suitable response...
 
u cud git 2x512 if u wan dem 2 B dul channel, r jus go 2 4gb n don wury bout D lost ram.

It's not just windows and microsoft guys.  x86 (32 bit) operating systems (including linux) as a whole can only address 4GB of physical memory, this does include video cards, there are alot of ways to tweak it but most tweaks won't change performance unless your messing with an MS Exchange server lol.
 
But it's really cheap for 2 x 2GB sticks of DDR2 800 that is definately the best way to go for sure.

Hmmm why does my 32 bit Windows server 2003 Enterprise edition support more than 4GB ram?  
 
lol evil grin  

...because it's a limitation in the consumer OSs.  

 
Honestly, that's what I'd like to know as well.
 
XP and Vista x86 have the upper level limit dictated by hardware, but Server 2003 (all flavors) do not.
 
I've heard explanations about PAE, but XP, 2003, and Vista all support PAE.  
 
Then again, I also heard that PAE was crippled in XP and Vista because of poor drivers and was only enabled because of DEP.  This would make sense, since most server builds are built with tighter requirements (the HCL), and consumer PCs are not built with the HCL in mind at all.  

I was just having fun with that post and wasnt trying to hijack the thread but if you really want to know look here.
 
http://support.microsoft.com/kb/283037
 
and if you are really want to sift through technical mumbo jumbo
 
http://blogs.mssqltips.com/blogs/c [...] oh-my.aspx