Why can't I use all of my PC's RAM?

Well, I have Win 7 64 bit and 8 gig of ram and its saying I can only use about 6 gig of it. I have a 1 gig graphics card but all together that's 9 gig but can't the 64 bit version of Win 7 use 16 gig of ram? I'm confused.

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frollard6 years ago
Might be...hmmm

Check in msconfig maxmem settings:
goto start> type in 'msconfig' no quotes

goto boot tab, hit 'advanced options'

see if the box labeled 'maximum memory' is ticked, clear that, and reboot.


hmmm...something to keep in mind: While your bios may be able to address x amount of bajillions, physically, the hardware might be limited if it's an older motherboard. Worst case scenario, 6 is still awesome.

When you go into your bios, what does it show about your system info?
owenp1 frollard2 years ago


Millawi Legend (author)  frollard6 years ago
I think the motherboard is new. I've had the computer for like 3 days. I'll just change the settings in msconfig and restart.
Millawi Legend (author)  Millawi Legend6 years ago
Yay! I did what you said and now I can use the full 8 gigs.
sweet! Don't forget to mark best answer if it solved your problem :D
Excellent answer!
nick0965 years ago
hmm, i tried to do exactly that but i still cant use my 12Gb RAM, just 4GB
i guess you have a 32bit operating system which can only use 4gb's, if you want anymore than that you need 64bit
Comp-Ace5 years ago
frollard gave the best answer for this disturbing issue..i did experience it once...but still some systems reject certain types of memory brands most probably has to do with FCC and ISO standards

Try using RAM Sticks of the same Brand with equal DDR(Double Data Rate) like if its 533,use those with a DDR of 533 all through.

Point of correction to those who are saying that Windows 7 can be using 3GB of RAM at start up or when no Heavy programs are being executed because it barely takes half a gig + maybe 1 gig for those who have high end graphics cards with that much dedicated video memory. bearing in mind that they have their own memory
MRedu6 years ago

8GB is a lot of PC memory! are you sure you need all of it anyway? What lemonie said about windows 7 using upto 75% for the system seems like the logical explanation.
lemonie6 years ago

6.07 isn't round, even at 1024 bits per K, I'd say the rest is used / reserved by Windows 7.
75% of RAM up to a maximum of 128 GB sounds about right.

Re-design6 years ago
The memory in the vid card is only usable for the video card.

The other memory is taken up by the os and various programs that load at boot up.

The rest of the memory is what you have left to actually use for the programs you run.