8GB installed. 4GB usable.

[LNERlover5]

Hello, this is an issue I cannot seem to resolve so any help would be appreciated

After replacing my single 4GB Crucial Ballistix Sport 1333MHz DIMM with two Corsair Vengeance 4GB 1600MHz DIMMs my system seems to refuse to act the way I wish it to. 4GB is seen in the BIOS. 8GB by Windows and CPU-Z but with the other 4GB being system reserved.

I have tried various methods such as msconfig, ect. Non seem to bear fruit however...I have flashed the BIOS to the latest non beta version. which seemed to both be a fix and a break, as before the flash the BIOS saw 8GB of RAM but Windows would not boot. Post flash 4GB was seen and Windows would boot.

Specs.
Asus M5A78L-M LX
AMD Athlon II X2 250 Stock Clocks
Corsair Vengeance 8GB 1600MHz

Thanks

 

[clam1952]

Will that board take 1600Mhz? according to specs it's a max of 1333 unless there's been a bios update, try using the bios default for the memory settings and voltage, worry about the speed after you get it working.

Hmm this is odd was looking at the specs in Ebuyer, they seem to have 2 different ones for ram on the same page, according to Asus you should be ok with 1600.

 

[bunkerrattmk2]

check the Memory Remapping Option in the BIOS. You have to enable it to use your complete memeory.

 

[trainfan2017]

Are you using 64bit windows ?

 

[slabay]

check the Memory Remapping Option in the BIOS. You have to enable it to use your complete memeory.

Don't forget that just by dropping the bigger DIMMs doesn't necessarily mean that the motherboard can reference that much memory.

For what it is worth, trainfan2017 seems to hit the nail on the head. If you go to the Asus page for that motherboard, it says that even with 4GB installed, it can only reference 3GB using 32-bit Windows. You'll need a 64-bit version of Windows.

 

[fran1]

2 x DIMM, Max. 8GB, DDR3 1866(O.C.)/1600(O.C.)/1333/1066 Hz ECC, Non-ECC, Un-buffered Memory
Dual Channel Memory Architecture
* Refer to www.asus.com or user manual for the Memory QVL (Qualified Vendors Lists).
* Due to OS limitation, when installing total memory of 4GB capacity or more, Windows® 32-bit operation system may only recognize less than 3GB. Install a 64-bit Windows® OS when you want to install 4GB or more memory on the motherboard.
* AMD FX Series CPU on this motherboard supports up to DDR3 1866MHz as its standard memory frequency.
* AMD AM3 100 and 200 series CPU support up to DDR3 1066MHz.

Motherboard specs from asus.

 

[LNERlover5]

Thanks for the replies. I am running Windows 7 Home Premium 64-bit so OS limitations may not be the issue. The new RAM kit does comply with the qualified list, however I am running it at 1333MHz to work with the Athlon II.