Bios not recognizing ram after CPU upgrade

[Garviel]

BIOS will boot with a DIMM(s) checksum error (F1 to continue). I have 4 identical 1 gig G.skill sticks installed. They have been in for about four years. Anyway, before I installed the CPU, BIOS and Windows read them just fine. Now, BIOS only recognizes 2 sticks whereas Windows reads 4.00GB(2.00GB usable). I have tried re-seating them to no avail. I have checked in msconfig to see if max memory was checked. It was not. I've take out the CPU and looked for bent pins, damage. There is nothing there. I'm using a cooler master 101A and thought perhaps it was latched too tight. Removed it, placed the stock heatsink on and still just 2 showing up. But when I reinstall my Old CPU (Athlon X2 3.1 Brisbane) everything is fine. BIOS recognizes 4 sticks as does Windows. I've also cleared CMOS with no result.

Upgraded CPU: AMD Phenom II X6 1045T@2.7ghz 95 watts
RAM: 4096MB G.Skill DDR2 PC2-6400 (400mhz) (4 identical sticks)
MOBO: Foxconn A7GM-S 1.0 flashed to 799F1P15

Any ideas? I'm upgrading to 8 gigs (max this board can take) tomorrow. Just waiting for the package. I just find it curious that everything is normal once I install my old CPU.

 

[kick3]

I am having this exact issue. I just upgraded my processor and had to reseat all my RAM (4x1G) after a beep code error. Now I'm getting the same Dimm(s) checksum error and my system is also reading 4G 2G useable. I have tried the same steps as above.

mobo: Asus M3A79-T Deluxe
new cpu: AMD Phenom II x4 965
memory: G.SKILL 4GB (4 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066

it's driving me crazy because my system is now slower with a new cpu then it was with the old one.

 

[kick3]

ok, just read this: http://www.gskill.us/forum/showthread.php?t=723

but I cannot find where in my BIOS my memory divider is.

AMI v02.61 bios

 

[kick3]

http://www.techpowerup.com/forums/showthread.php?t=97640&highlight=m3a79-t

finally found it......it was only running at 400hz, but msconfig is still only reading 2g...time to check my cpu I guess....*sigh*

 

[kick3]

so CPU is reseated, no bent pins. Still receiving DIMM(s) checksum error. Still have 4g 2g useable

 

[Garviel]

Yeah, the error I was receiving vanished after I installed my new RAM. I had checked many forums and never found a specific answer to what the problem was. Once I installed the 4 new 2 gig sticks the problem vanished. It was very odd. Maybe the new CPU threw the voltages off (although they were reported accurate in CPUID) since the RAM was pretty old. Maybe it was the BIOS flash I performed. Could have been a combination of both the CPU and the updated BIOS.

If you haven't figured the problem out yet then maybe you should try new ram. It's cheap enough and more is always a plus