I search everywhre, but everywhere the tell another story (some say win7 32 has 3GB limit, some say 4GB)...So I want this to be clear:I have a machine (running WinXP Pro (default), it has 4GB RAM (XP does see 3GB, I know for sure that XP32 only supports 3GB)So I want to upgrade to Windows 7...Does Windows 7 (Ultimate) 32-bit support my 4GB RAM, or do I need to get a 64-bit version?

Windows 7 32-bit works the same as XP 32-bit with respect to RAM recognition. No difference. It will see 4GB, but only address 3.XGB. A 64-bit OS will see and address your 4GB or more of RAM.

Alright, thank you very mutch (both)!If I look at the factory website, it says it should be able to take 8GB, so I guess that won't be a problem. But now I know for sure that I have to install a 64-bit Win7... Thanks!

Hello SparkyRih, According to your description, please understand that the question is not caused by the Windows 7 product itself. Since you installed 32-bit OS, the system could only recognize 3.3GB although we find the total RAM is shown as 4GB in BIOS. If you need full use of 4GB ram, you should install 64-bit product on the computer. For more information on this subject, please refer to the following webpage. The 4GB Windows Memory Limit: What does it really mean? For your current situation, please purchase the Windows 7 64-bit OS; format the HDD and do a clean-install on the computer. Thanks for your time and understanding! Good Luck! Andy

Here are your answers: http://msdn.microsoft.com/en-us/library/aa366778(VS.85).aspx#physical_memory_limits_windows_7 Now my questions is...If I put 8gb in my laptop (knowing that Windows 7 will only support 4gb, will my hard drive start heavy file paging like Vista did? Or will it gently ignore the extra ram?

Here are your answers: http://msdn.microsoft.com/en-us/library/aa366778(VS.85).aspx#physical_memory_limits_windows_7 Now my questions is...If I put 8gb in my laptop (knowing that Windows 7 will only support 4gb, will my hard drive start heavy file paging like Vista did? Or will it gently ignore the extra ram? 32 bits OSs will only address 4gb memory whatever the OS is. Why would you want to put 8gb RAM if you use a 32 bits OS? Use 64 OS with more than 4 gb RAM.I've installed 8 gb RAM with Win7 Home Premium 64 bits and it's lightning fast. Use 64 bits OS if you want more than 4 gb but make sure your machine is 64 bits ready and you have all the drivers for your hardware.When you buy Retail (boxed) versions of Win7 (Full or Upgrade), both DVDs are included (32 and 64 bits), for OEM versions, ask the computer dealer.

check this plz,officail saying http://msdn.microsoft.com/en-us/library/aa366778(VS.85).aspx

32 bits OSs will only address 4gb memory whatever the OS is. That's not quit right. Windows Server 2008 Datacenter 32 Bit supports up to 64 Gb RAM. The here: Physical memory limits windows server 2008

And 32-bit Server 2003 Datacenter supports a whopping 128 GB. Magic. Since 1995. "However, "client" versions of 32-bit Windows (Windows XP SP1 and later, Windows Vista, Windows 7) limit physical address space to the first 4 GB for driver compatibility [3] and licensing [2] reasons, even though these versions do run in PAE mode if NX support is enabled."