Motherboard not recognizing full memory

[monsemat]

Hello, I have a question about my Asus P7P55-M motherboard. I have 2 DIMMs of 2 GB each installed on the first 2 memory slots (DDR3, 1333 MHz), but today I bought a 3rd DIMM (a 4GB one) but when I turn on the PC, it won't recognize it.
What could be the problem? It's a brand new DIMM. Thanks!!!!

 

[ko888]

I don't see any test of 4GB DIMMs on the P7P55-M Memory Qualified Vendors List (QVL). That doesn't mean it shouldn't work.

What is the brand and model number of your new 4GB module?

 

[rdc85]

I think u cannot run dual channel with that set of rams, so there maybe some setting in the BIOS need to be changed.. (not familiar with ASUS BIOS)

Quick test, test it with just the 4 Gb ram on the mobo.. see if it recognized?

Also u will need to put the both 2 Gb on the same color slots, and the 4 Gb in the other ones ....

 

[ko888]

The two 2GB modules should be installed in the blue memory slots. The blue memory slots are located at the end of the memory bus. Placing the two 2GB modules in these slots properly terminates the memory bus preventing signal reflection.

The 4GB module should be installed in one of the black memory slots.

 

[monsemat]

Thank you all for your help! As it turns out, the DIMM was defectuous, I got a replacement one and it worked! I did however put it on the 4th slot B1 instead of B2 because otherwise the motherboard will not recognize it (Info checked on the ASUS site)! Again, really appreciate your help!!!

 

[rdc85]

Glad it's all works out..