Laptop weird after RAM install?

I have an Acer Aspire ES1-521 which I recently bought. It worked perfect and ran quite smoothly. I was foolish and decided to change the RAM myself and now it is acting strange. I'm pretty sure I installed the RAM fine. When I can get to the desktop it shows 12GB RAM which is what I upgraded to. My problem is sometimes it just hangs at startup and says "Diagnosing". Sometimes I can skip it and go straight to Windows 10 but it is extremely slow. What exactly would cause it to slow down after installing RAM which seems to be fine? Maybe I didn't connect everything back perfectly but which part would cause it to act this way? Thanks for any help.

 

Is Win10 x85 or x64? And are those brand name RAM or 2nd hand? And did you install one at a time to see if they worked? Alot of things you need to do before hand before posting as no one here has your laptop with them to diagnosis it.

 

Hi, I only replaced 1 stick. I have x64.

 

Remove the stick you installed and see if it boots properly. Then reinsert the stick and see if it works. It is possible you just got a bad stick of RAM or it could be improperly inserted, sometimes they can look properly inserted. but they aren't.

 

You can also try switching the RAM modules in the different slots too. Again; try switching with just a single module installed and then after you are satisfied with the stability***, add the second module and test again.


***Use the Windows Memory Diagnostic tool to check if the RAM is okay.