Memory problem

[hodad]

Just installed 2GB (2 x 1GB) in the 3rd and 4th slots on my motherboard, and the computer won't even boot to the bios setup screen. The memory modules are identcal to the modules in 1st and 2nd slots. When I take them back out, pc boots just fine.

I'm assuming it may be a parameter that need to be tweaked on the bios, but not sure. Memory modules are fine, I can swap them with originals, and they work too.

Particulars:
Gigabyte GA-MA785GM-US2H
Samsung 1GB 1Rx8 PC2-6400U-666-12-ZZ
PN- M378T2863RZS-CF7
240 Pin DDR2
Chipset Nothbridge AMD-785G
Southbridge AMD-SB710

Anuy help would be appreciated. PC works fine with the 2GB, but I figure I may as well put in the extra 2GB. Can't seem to find any data on these modules, even at the Samsung site!

 

[o1die]

You can try resetting the bios by removing the board battery for one minute with the system unplugged. Might get you to the post screen. To run the new modules, your board has to automatically set the command rate to 2T, and use "unganged" or "memory mapping" settings. Normally, these settings will already be set correctly in the bios. Other post settings are using manual mode to set the ram voltage and speed. I've tried setting the timings manually, but never had much luck with it. Good luck.