OptiPlex 755 8GB 800mhz RAM

[2690173248]

I have my OptiPlex 755 in A22 modded BIOS (for Xeon microcodes) with Xeon X3363. I have 2 Kingston KVR800D2N6 2gb 800Mhz sticks and 2 Transcend 2GB DDR2 800Mhz sticks plugged in. No matter what slots each sticks go in, I only get 667mhz speed, though it is in Dual Symmetric and everything else is fully functional. If that's something I can let slide, the machine also sits at RAM testing stage for 10 seconds before post screen comes up. That 10 second delay disappears if I boot the machine up right after shutdown. The RAM sticks are tested by memtest86 with no problems. Downsizing it to 6GB (2x2gb and 2x1gb) solves the problem. Do I have any luck for 8GB 800mhz RAM and without the boot time lag? the 10 second lag is annoying because this desktop has SSD.

 

[william p]

These old Dells need low density RAM. This means chips on both sides of the module. As far as actual performance it doesn't make a lot of difference with a modern GPU that has 2Gb or more RAM, the system memory is basicallt on the sideline most of the time. The slowest DDR2 to the fastest only ammounts to a couple % difference. But if there is just one chip that runs 667 then that's all your going to get.

 

[2690173248]

Hmm I solved the problem. I was having pairs of Kingston and Transcend RAMs in 800mhz and they simply just don't work together as 800mhz. Swapped the Transcend RAMs with something else that I traded with someone else completely solved the problem!