I just found that even 64 bit version of Windows 7, if on some computer whose BIOS doesn't support it, then we are back to 3.25GB RAM limitation... back to the old days of 32 bit...

Now, how can we be sure the computer we buy next can support the full 4GB instead of paying full price for that last 1GB but getting 0.25GB out of it?

I think one method is that if that computer lets you choose to have 6GB or 8GB or 9GB (such as the case of some desktop like Dell's XPS 9000 which you can configure on the net), then in that case, you can be sure if you buy a 4GB machine, then it most likely can support the full 4GB -- otherwise it makes no sense to sell you the 6GB or 8GB models... if they are limited to 3.25GB.

If it is an HP or Sony notebook with 4GB, then maybe it is worth it to go to a store like BestBuy to actually right click on My Computer and see the usable portion (unless the manufacturer somehow adjust that line to make it look better like in the Vista 32 bit days).

4 Answers 4


The 3rd party memory manufacturers have vast databases about memory types, capacities and configurations for pretty much every mainstream PC and motherboard. If you look your machines up in there it should say what the maximum memory capacity of the machine is, along with any caveats for that system.

For example Kingston have one here: http://www.kingston.com/branded/default.asp (start by picking the manufacturer from the drop down on the right hand side).

  • The question is about PCs not being capable of running more than 3.25 GB RAM. It has nothing to do with the memory itself.
    – alex
    Nov 9, 2009 at 12:05
  • 2
    +1 Kingston's site will tell you if the system or board supports the full 4GB or only up to X due to it's own limitations. I use this regularly to check before a purchase. The Transcend sites also does this. Nov 9, 2009 at 12:15

If you're buying a 64-bit Windows 7 machine in a retail store, it's almost always going to have at least 4 GB of RAM and the BIOS is most likely going to support it.

I'm guessing, but I imagine that the BIOS limitation to which you are referring probably applies to older hardware architecture. Thus, if you were upgrading a 5-year-old machine, you might find difficulty in accessing a full spread of RAM.

I recently upgraded a Dell Dimension 9200 that I had purchased in 2006. It originally came with Windows XP 32 bit and I was able to put Windows 7 64-bit on the machine with full access to the 4 GB of memory installed.

  • I see... my Dell Inspiron 530 is a 2008 model... with 64 bit Win7, it says it is only 3.25GB. Nov 9, 2009 at 15:37
  • Thanks for letting me know that. That's somewhat of a suprise to me on a 2008 model. However, Dell might have been cutting corners on that particular model. Have you tried flashing the firmware with the latest ROM from Dell? I had to do that to make my machine compatible with Vista. Nov 9, 2009 at 16:00

Look for a machine with a logo saying Compatible with Windows 7.

Microsoft provide a scout to help you select or check a proposed purchase.

  • 2
    the 3.25GB ones are "compatible" with Windows 7 too... Nov 9, 2009 at 9:50
  1. Have a look at machine's specifications at the manufacturer's website before buying it.
  2. If you already bought one, that should support 4+ GB RAM, and though it doesn't, have a look at manufacturer's support... Or machine's manual and BIOS settings.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.