6400U and 4200U compatibility

[Countrybumpkin]

I am trying to add a little more ram to my PC. Right now it's got 4gb, 2 1gb cards and 1 2gb card of 6400U. I read somewhere that 6400U and 4200U are compatible, so i put a 4200U card from an old PC in the empty card slot. However, when I powered on and checked my ram, I was still only showing 4gb total. What gives? Is there a reason my machine isn't recognizing the the 5th gb? are 6400 and 4200 actually not compatible?

 

[codefeenix]

What OS are you using? Is it 64bit or 32bit?

 

[captaincranky]

First off, some boards can't handle more than 4 GBs.

5 GB is sort of a silly number anyway. If yours is a dual memory channel board, it's possible to force it into single channel operation with an asymmetric configuration, such as the one you've just created.

 

[Countrybumpkin]

I was running Windows XP 32 bit, but i recently upgraded to Windows 7 64 bit in hopes that I would be able to run more ram. I'm pretty new at this stuff, but my "computer" section of device manager says that I am running "ACPI x64-based PC". In terms of make and model of motherboard, I'm not sure how to figure that out. I was thinking about going out and getting a 2gb card of 6400U to fill my empty ram slot, which would put me at 6g, but if my motherboard can't handle it I guess I won't waste the money. Hopefully I posted enough information to give yall a little more insight.

 

[crunchie]

If you are not sure of the Motherboard, download a smal tool called CPU_z and run it.
zgo to it's mainboard Tab and it should tell you what the motherboard is.

 

[Countrybumpkin]

Thanks for that link and the heads up about the program. My motherboard is the M3A32-MVP DELUXE by ASUSTeK Computer INC.

 

[crunchie]

Looks like you can run 8Gb, but to be honest, you should be looking at identical RAM to get the best out of them.
What processor are you running? AMD processors can have a lot of trouble with stability running more than 4Gb of RAM, especially at higher frequencies.

 

[Countrybumpkin]

I am running AMD processors. according to CPUID, I have the AMD Athlon 64 x2 Dual Core Processor 5200+. I was considering going out and purchasing a 2 gig stick of RAM this afternoon. Should I be okay with another stick of 6400U in this processor and motherboard? That would put me at 6g total.

 

[crunchie]

Dependent on the processor, it could be ok. Some have better memory controllers than others and only a practical test will tell.