Ram specs have nothing to do with the psu.
Back to your original post.
What exactly is your problem?
Do you already have some ram that is not working properly?
Test with memtest86+
Speed is irrelevant to performance with intel processors, so do not sweat that.
Or, are you looking to upgrade your ram?
Go to the ram web site and access their ram selection app.
Enter your motherboard and you will get a list of their compatible ram.
You want supported ram, others might work, but you are on your own there.