4gb ram but 3gb usable

I have windows 7 64bit and i bought 1gb extra ram. When i installed that, it says 3gb usable. I flashed bios and unchecked maximal memory (msconfig).

Mobo: gigabyte GA-P31-DS3L
GPU: Nvidia geforce 8800 gts 640mb
Cpu: Intel core 2 duo e8200 2.66 GHz
Rams: Apacer DDR2-SDRAM PC2-6400 2GB (Yellow socket)
Apacer DDR2-SDRAM PC2-6400 1GB (yellow socket)
G.Skill F2-6400CL5-1GBNT 1gb (red socket)
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  1. I'd try the two 1GB sticks in the red sockets and the 2GB stick in the first red socket (closest to CPU).....reboot and see what it says in BIOS for system memory. Come back with results and we can take it from there.
  2. I put 1gbs into yellow sockets and 2gb into red socket (closest to CPU) - pc restarting at the black screen
    I put 1gbs into red sockets and 2gb into yellow socket (closest to CPU) - nothing changed
  3. I put 1gbs into yellow sockets and 2gb into red socket (closest to CPU) - pc restarting at the black screen
    I put 1gbs into red sockets and 2gb into yellow socket (closest to CPU) - nothing changed
  4. Try all the sticks individually! It looks like one is faulty.
  5. No faulty one
  6. I'm sorry for the confusion, I meant to say to put the 2 1GB sticks in yellow slots and the 2GB stick in red but you did that already. As other user said, did you try them individually (only boot with one installed at a time)?

    One of these has got to be faulty because you said the problem started happening after you added 1GB. Why did you flash BIOS? I'd boot into BIOS and set back to defaults and see how that does, with the two original sticks as they were without the one you added....are these RAM sticks all same speed/latency?
  7. I tried them individually, every stick in every socekt but there isnt any faulty one.
    They all have 800 mhz.
    G.Skill latency: CL5-5-5-15
    apacers latency: CL5 (couldn't find other numbers).
    When i have 2gb and 1gb installed it says 3gb, but if i install other 1gb, it says 4gb (usable 3gb)
  8. Hmm...read Note 1 - http://www.gigabyte.com/products/product-page.aspx?pid=2615#sp

    "(Note 1)Based on standard PC architecture, a certain amount of memory is reserved for system usage and therefore the actual memory size is less than the stated amount. For example, 4 GB of memory size will instead be shown as 3.xx GB during system startup."
  9. That means, it suppose to be like that?
  10. Often it's a chipset limitation (addressing) limit, and it's not your OS limit.

    Example: Installed vs Total (less hardware reserved) vs Available (less OS, background & Apps)

  11. My chipset limitation is 4gb and hardware reserved shows 1024mb and installed 3gb, but i have 4 gb in my computer
  12. In your manual (page 16):
    Due to chipset limitation, read the following guidelines before installing the memory in Dual Channel mode.
    1. Dual Channel mode cannot be enabled if only one DDR2 memory module is installed.
    2. When enabling Dual Channel mode with two memory modules, it is recommended that
    memory of the same capacity, brand, speed, and chips be used and installed according to the
    configurations in the first table for optimum performance.
    3. Because of chipset limitations, do not populate both DIMM sockets of the same channel
    (e.g. DDRII1 and DDRII2) with double-sided memory modules to prevent system's failure to
    start or incorrect detection of memory modules.

    Also note the DS vs SS placement. The trouble is figuring out which if any is DS or if SS/DS mix is the problem. So look at the figures for RAM placements.

    Try the following:

    CPU: DIMM 1 | DIMM 2 | DIMM 3 | DIMM 4

    CPU: 1 GB | 1 GB | 2 GB | blank
  13. tried but nothing changed. (G.Skill is SS)
  14. There's 4 combinations for potential SS/DS mix as shown in your manual on page 16 (Three Modules) so try them all - http://download.gigabyte.us/FileList/Manual/motherboard_manual_ga-p31_ds3_ds3l_s3l_e.pdf
  15. I have two DS and one SS
  16. vortextech said:
    I have two DS and one SS

    The you're SOL, get new RAM or live with 3GB.
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