BIOS recognizes full 8GB RAM, Windows (my computer) only recognizes half 4GB RAM

I have a
toshiba qosmio x505 q870
intel core i7 @1.6 GHz
windows 7 home premium 64-bit

I had 4 GB ram in my pc and it started to give me bsod. I checked my computer and it showed I only had 2 GB ram. I figured i needed new ram so i bought 2 sticks of 4 GB (8 GB total). I installed it and went to my computer and saw 8 GB ram. I wasn't using my computer for more than 5 minutes before it went to bsod. I restarted and went into windows again and got bsod after 3 minutes or so. I restarted and went into my computer and saw I only had 4GB ram. I restarted and checked BIOS and it said I had 8 GB ram. I got bsod again today and i restarted and it showed 4gb ram again. (I should also mention when it goes to bsod and only loads windows with 4GB ram, windows loads very slowly)

I am at a loss... why does my BIOS show 8GB ram and windows too, but then windows decides not to show all of it randomly?

my pc runs fine with 4gb ram
12 answers Last reply Best Answer
More about bios recognizes full 8gb ram windows computer recognizes half 4gb ram
  1. Download and run memtest86
  2. i7Baby said:
    Download and run memtest86

    I did and I got errors.
  3. Provide the model/serial no of the RAMs which you purchased.

    Your PC has support for max 8GB DDR3 @ 1066MHz, memory type of 204-Pin DDR3 SO-DIMM.
  4. Did you run the test with both modules at a time or did you check them one by one? Pl check them one by one with memtest86. Getting error in memtest86 means a bad ram.
  5. G.SKILL 4GB 204-Pin DDR3 SO-DIMM DDR3 1066 (PC3 8500) Laptop Memory Model F3-8500CL7S-4GBSQ

    I ran with both with errors, then ran one pass in each slot with one module with no errors. I didn't have time for much more.
  6. Money vs time. Just buy new ram then.
  7. Pl update the BIOS of the mobo afterwards clear its cmos. If problem is not gone by then and you don't have time for further testing then buy new RAM
  8. Okay I ran both sticks in both slots 1 pass each. The first stick had an error in the first slot.
    First stick in second slot no errors.
    Second stick in first slot no errors.
    Second stick in second slot no errors.

    I ran the first stick in the first slot again with no errors this time the first pass. I am letting it run for at least two passes each now.

    Any ideas?

    How do I clear cmos? Thanks

    Update: I ran 2 passes on the first stick first slot with no errors, but now I put both sticks back in, checked the BIOS and I only show 4GB ram...
  9. Best answer
    Maybe its dirty dimm slots. Try cleaning them and the ram sticks.

    Clear cmos - power off. remove the motherboard battery. wait 10 mins. put the battery back. power up.
  10. As you are using laptop, better go into BIOS and select the BIOS defaults option. Save the changes and exit.
  11. About 6 months ago I had an overheating problem ended up that basically everything was dusty so I blew it out and my idle running temp went from 80 to roughly 60 just like that.

    Just yesterday I took some air and blew out my slots and my pc again and got some more dust. Not anything visible from the ram slots but apparently enough. 2 days with both sticks in with no problems. Keep crossing my fingers!!

    Thank you for the help
  12. man i have the same problem if u fix yours u can help and me?
    bios regnonize half ram (2+2 gb) and i dont know why no work 1 slot...
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