I have a free RAM slot and some spare memory that will fit my computer. However the problem is my motherboard only supports 2GB and I have 2GB installed. What would happen if I plugged the spare memory in the RAM slot?

The following things spring to mind:

  • Nothing will happen
  • It will work, computer becomes faster
  • Computer becomes slower
  • Explosion
  • Undetermined (Any of the above)

Does anyone have any experience of this?

Update: Egged on by you zealous lot, I went ahead and stuck the extra memory in. It booted up! Unfortunately, the hunch of some has been proved correct. The memory is reported at the capped limit, rather then the actual available. A shame then! But thank you all for your suggestions, speculations and stories.

For your reference, I am using a Dell Insprion 6000 with 2gb installed, latest drivers. I attempted to add 512mb, with no success.

  • Funny to see so many answers and so little upvotes :P
    – Ivo Flipse
    Aug 26, 2009 at 18:21
  • well, Ivo, no point in voting here, since it is more or less guesswork until we know the mainboard model and type of memory, only then you may get accurate answers, either from experience or research.
    – Molly7244
    Aug 26, 2009 at 18:32
  • Good point ;)
    – Ivo Flipse
    Aug 26, 2009 at 18:53
  • Did you flash the BIOS? Jul 16, 2013 at 16:08

14 Answers 14


Simple answer: It either will only see the max supported memory or it will not work at all.

My gut feeling says two things:

  1. If it does work, you just will not see the extra memory, only the max the motherboard/chipset supports.
  2. If it doesn't work, it usually will just beep at you with a memory error and you will get no video response. All depends on the motherboard depending on how it handles memory errors.

Someone on Yahoo Answers says an interesting bit about getting a blue screen due to this:

In my experience, putting in more than the max amount of RAM as specified by the manufacturer will cause the computer to not boot up.

others claim:

Some won't POST, some will and simply BSOD (kernel panic, etc) with PFN_LIST_CORRUPT.

That said, the "max" memory isn't always the actual max. Case in point, Intel states the GL960 chipset (such as in my laptop) supports a max of 2GB of memory. 4GB is a no-go, but 3GB works.

  • Hmmz from reading other forum posts it seems any of your own suggestions are possible...
    – Ivo Flipse
    Aug 26, 2009 at 18:05
  • There ya go, your answer was more awesome looking, so I just added my stuff to yours and deleted my orginal.
    – Troggy
    Aug 26, 2009 at 18:32
  • Yah, Ivo needs the rep more than I do. ;)
    – Troggy
    Aug 26, 2009 at 18:37
  • 4
    I've actually seen a few cases where a board accepted more memory than the max listed in the official documentation. What I believe was going on was that they implemented the hardware/bios to support the largest possible capacity and wrote their documentation to support the largest commercially available dimm size. Feb 26, 2010 at 21:46
  • 2
    Way back when, I tried to put 16 MB of RAM into a system that only support 8MB. It booted and showed me I had 8 MB of RAM. I was sad because that was a lot of money in those days. Carmaggeddon ran great though ! I mean, CorelDraw, yeah, that's what it was for... Jul 16, 2013 at 16:06

your first stop is the mainboard manufacturer's website. update the BIOS to the latest version. then fit the additional memory and turn on the computer, if the memory is detected, run MemTest86+. no, it won't explode! :)

  • now that we know it's a Dell, i hate to tell you: they're rather conservative when it comes to BIOS updates, especially those kind of updates that allow for a faster CPU and/or more RAM. they prefer to sell you a new computer. :)
    – Molly7244
    Aug 26, 2009 at 19:53

Depends on the board and BIOS. I have a Sony VAIO VGN-Fe770G that uses the GM945 chipset -- Intel, Sony, AND Crucial say that the maximum amount of RAM is 2GBs of DDR2 (1 GB per SODIMM slot), but I'm running Windows 7 x86 with 3GBs and both the BIOS and Windows report (and presumably map) all 3072MBs. I'm going to try with a second 2GB DDR2 SODIMM and see if the BIOS and a 64-bit LiveCD OS sees 4096MBs.


This really depends on your MotherBoard. I have seen some cases where the system functions as normal but will only recognize the 2gb, and I have seen some that will not start up and throw an error.

I have yet to see any of the hardware fail because of an "over-installation".


I tried to installed 4GB on a HP 6720s that only supports up to 3GB, and what happened was that the BIOS saw the memory, but with any type of memory check an error was reported.

And trying to install an OS (not even x64) was impossible, I got a memory related BSOD every time.

I found out later on that some 6720s moderboards supported 4GB, but not mine... :(


Been there, done this. The BIOS complained about the RAM and refused to start up. I had to downgrade again. But this was an old Pentium 133 from Dell and about 4 PC's in the past.

In general, it will depend on the BIOS and hardware. It won't be able to handle the big modules but if there are still smaller modules available, the system might decide to just start up with the memory of just the smaller modules. But in general, the BIOS won't be able to use it thus your system would have no free RAM to use.


I've done it on an older computer, and the computer booted just fine - however the BIOS / start up scrolling list only reported what the maximum for the motherboard was, so it was presumably ignored.

Now wether that's unsafe or not, i don't know, but i'd simply leave only up to the max in to be safe.


Assuming that you install the correct type that this motherboard accepts, anything above 2GB won't be addressed and will be ignored.


I have an HP Compaq dc7600 desktop with an OEM-reported 3GB max. I have 6GB installed. The BIOS and Windows 7 Ultimate both recognize the extra RAM, but sysinfo shows:

Installed memory (RAM): 6.00 GB (3.25 GB usable).

Even so, when I upgraded from 4GB (which was already over the max) to 6 GB, the processor usage decreased across the board. Not being an engineer, I can't explain it, but it's not my imagination.

One possibility I thought of is that although the memory may not be directly accessible, Windows does "see" it and thus is more brave in its allocation of RAM resources versus virtual memory.

  • interesting.. I wonder if XP has a program that says how much memory is usable.. is there a third party app you can try that'd report it? that could be used in xp
    – barlop
    Feb 11, 2012 at 16:47
  • 2
    You can use all 6 if you use a 64 bit OS. 3.25 is the normal limit imposed by a 32 bit Windows.
    – Tonny
    Nov 1, 2013 at 15:35

I haven't tried this but I think the motherboard will just completely ignore it.

  • That's not always true, see my post below.
    – TFM
    Aug 26, 2009 at 18:11

I got a 2.5GB with system limit of 2 GB and it works.


Im using an emachines d620 notebook. Recently it became very slow and the system health report suggested i decrease the load or upgrade the memory. I did later by taking my pc to an expert who installed a 2gb memory module. The initial RAM was 1GB. The guide set the limit of RAM that can be added at 1GB. My RAM is now 3GB and the rest of the memory that is not in use is shown as being available. Believe me my pc is working perfectly and its faster than ever.


I have an Hp Pavilion 7935 that supports a max of 512mb of ram. I have installed 1 gig in it. currently using it that way. It boots and runs fine (Bios shows 992 Mb)


the mother board just ignore it. My computer is a HP pavillion a1600n max of 4 GB and I have two slot with 2 GB and two other with 500 MB and the computer read only 4 GB

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