PC doesn't boot after adding RAM

Question

I have Lenovo M91P 7052-b5u i5-2400 (spec sheet) with 2+1 GB RAM

.

Because I have 4 sockets, I decided to add 2 more.

Yesterday I added Kingston 4+2 GB RAM 99u5471, but the PC didn't boot. It was black screen - no POST.

I thought maybe the new RAM wasn't compatible - but after I took out the old 2+1 RAM, everything worked just fine.

So right now the PC boot only if I putting OR only the old RAM OR only the new RAM but not both of them.

What can cause this? Is it because the size is different? (the Kingston is smaller than the old ones)

(I already tried to switch between the sockets)

Thanks!

Solution 1

Try replacing the BIOS battery before adding new RAM modules, then check the new RAMs one by one to see which works. When you are dealing with RAMs, sometimes PCs won’t boot, because it needs a BIOS reset, even if the RAM modules are working well. Also, different types of memory modules don’t work together in some cases – they must be the same make and model to work correctly.

Solution 2

You can't combine registered and unbuffered RAM on the same motherboard at the same time. Your existing RAM was registered, the RAM you added was unbuffered.

Comments

[Admin]

My best guess is a difference in speed between different types of RAM chips. Getting the same make/model for all chips may fix this. (Yes, that might mean replacing some working equipment in order to get some more-compatible equipment.)

[Dvir Naim]

crucial.com/usa/en/compatible-upgrade-for/Lenovo/… - can't see nothing about it...

[Dvir Naim]

Tried.. didn't work... Why different types are causing trouble..?

[George G.]

Even if specs are same but because they are from different manufacturers that may cause compatibility problems... Some different RAMs works together, some not. I think that's the case

[Dvir Naim]

there is nothing to do ha..? Out of curiosity - does the size says something about the performance?