Is there a simpler way besides opening the lower slot on a iMac to see which memory slots are taken?
I'm not asking this because I'm lazy, but rather because I have no physical access to the iMac from here, so I can't crack it open myself.

I've heard of CPU-X but that just checks the processor speed right?
I just want to see which slots are taken so I can purchase the right amount of memory.

Thank you for your reply!

In system profiler, under the Memory section, it will show you the memory slots and what, if anything, is in each slot.