Testing RAM slots is important for a few reasons. First, if your computer is having problems booting or running certain programs, it could be due to a problem with the RAM.
Secondly, if you are upgrading your computer and are not sure which RAM slots to put the new memory in, testing them can help you make an informed decision.
To test a RAM slot, first make sure that your computer is turned off and unplugged from the wall. Next, remove the cover of the memory slot where you want to test it. If there is a CPU fan in the slot, be sure to remove it before testing the RAM. Now insert one or more memory modules into the slot, making sure they are correctly seated and facing the correct direction (the black wires should be facing outwards). Replace the cover and re-connect your computer to the wall power supply.
Turn on your computer and check to see if it starts up normally. If not, check to see if one or more of the memory modules is defective. If one of the modules is defective, you can replace that module with a new one and continue testing. If all of the modules are working correctly, you can be certain that your RAM slots are okay and you can move on to installing your new memory.