[SOLVED] PC won’t post with new RAM

[GeorgeCZ75]

I have a dell optiplex 790 motherboard only rated up to 1333mhz RAM. I was running 8GB of 1600mhz RAM (four 2GB RAM modules). My pc posted and ran perfectly before my RAM upgrade. The memory was underclocking at 1067mhz So I decided to purchase a 16GB 1600mhz 4 stick RAM kit. I put all 4 sticks into all 4 DIMM slots and the pc didn’t post. I decided to troubleshoot and found that only 1 stick of ram worked. The pc posted with that 1 stick of ram and I saw that it was running at 1333mhz. I also tested with my old RAM to make sure it wasn’t the motherboard. What I found out was that if the RAM is good, the pc usually power cycles a little before it posts. What could be the issue here? I already tried resetting the CMOS multiple times. I let my pc run for a bit and laid my hand on the RAM sticks, they were hot.

 

[jojesa]

What's the model of the 16GB kit you got?
I have used Crucial 16GB Kit (2 x 8GB) & (4 x 4GB) DDR3-1600 UDIMM without issues on several Opty 790.

 

[kaehligj]

Go to the dell optiplex 790 support side.
Under support/download you will somewhere find a pdf file with a ram QVL list.

If your ram is not listed in this table, you wont rid the problems you have.
Any ram not listed in the QVL is NOT guaranteed to work in the mobo.

 

[GeorgeCZ75]

CML16GX3M4A1600C9B Corsair RAM. But how did my PC post with that 1 stick of RAM if it isn’t QVL supported?

 

[kaehligj]

Can you find this in the QVL - I can not spoon feed you, please do some yourself