Question Black screen after new RAM

Jul 17, 2019

I recently bought 2x8gb RAM modules of 2666mhz. Now both my CPU and GPU should work with these:

intel i5-7640x and Gigabyte Aorus x299

When i use the new modules my screen flickers/goes black and when it does boot it's very slow and crashes after a while. When i replace a new module with one of my older ones of 4gb 2400mhz it works fine. When i use both new modules and an old one in my 3rd slot it also works fine except it runs at 2400mhz instead of 2666, it shows available RAM as 20gb. I used the Windows memory check (mdsched.exe) and it doesn't come up with any problems, I updated my BIOS and enabled XMP again as well since it reverts to default settings after the update.
The option to manually set my RAM speed in BIOS menu is greyed out.

Thanks in advance!


What are your full system specs?

Can you test the new modules on another PC?

You can get the bootable memtest86+ from here, use an application like Rufus to copy the ISO to a USB flash and make it bootable; or use the auto-installer to make USB bootable.

Change boot priority and boot from the USB and check the new modules for errors. One RAM module at a time and at least 8 passes. Do more than one if it defaults to 4 passes.