Create a bootable-USB with Passmark's MemTest86 . If you can run through two complete long passes with 0 errors, your ram memory is working properly.
Other than using Dell Diagnostics, what method would you use to check your systems RAM for problems? For more questions regarding this contest, please visit the Information Page here.
DS 07/22: How can you check your systems RAM for problems, without using Dell 
Diagnostics?