Question Why is my pc not detecting the ram I added to my old pc?

BigC847

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Nov 2, 2014
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My friends PC was built a decade ago and wanted to add some ram to pep it up a bit. After installing ram, the computer posts, but doesnt recognize the additional ram.

Gigabyte ultra durable 3 mobo
i7 975 processor
Windows 7 pro 64 bit
Existing ram: 3x 2GB ddr3 2000 CL 9:9:9:27
New ram: 3x 4GB ddr3 1600 CL 9:9:9:24

I have no experience with 3 channel ram, so I dont know if there is a compatibility issue that would be different than dealing with dual channel.

Is it that they are different speeds? I thought the the ram would average to the lowest speeds when you have different clocks as long as each channel matched.
 
Different ram does most of the time not play well together. Some tinkering is needed.
Does the new ram work on its own? resetting cmos after installing different ram some times helps.
Different ram does most of the time not play well together. Some tinkering is needed.
Does the new ram work on its own? resetting cmos after installing different ram some times helps.
Okay, thanks. Yeah, my next step was going to be taking the old ram out and seeing if the new works on it's own. If it does, I will stick the old ram back in, reset the cmos and see what happens. Thanks!
 
Yes the new ram is slower. You'll have to lower the old ram to run at the slower speed but that is not a guaranty that it's going to work.

Yeah, nvm. You should just give up. Get all new ram and take out the old one cause you got ram of different sizes also. So different speed, different sizes, different timings, probably got the ones with different voltages also.

I had a X58 board till 2 months ago so I know.