AMD R9 390x Suttering/Major FPS Drops

[xslayerx10]

I've been having trouble with my three R9 390x's. In most demanding games, it runs them pretty smoothly. But, there is a constant stuttering/dropping of frames. I've been looking for a solution to this problem for a while before coming to post on here, so I don't sound like an idiot, but I fear that that is inevitable.

I've tested the issue on Heaven Benchmark, and I was correct. My average FPS on "High" (might have been ultra, not sure) would be about 200-250fps. But, then the low FPS would be something absurd like 3 or 10. Just watching the FPS counter, even though it changes rapidly, I could tell that the fps would be 200+ then drop to something around 90, or even lower. Looking through tons of solutions found on here and on the internet, nothing has seemed to work.

Solutions I have tried:

• 
  Using DDU, then reinstalling new drivers. No effect.
  Limiting temps so they don't exceed 80C. Problem persists.
  Cleaning the cards themselves.
  Made sure that my CPU wasn't bottlenecking anything.
  Enabling CrossFire, nothing.

Specs:

• 
  MB: Asus X99-A
  CPU: Intel Core i7-5930K
  GPU: AMD R9 390x (x3) Driver: 18.7.1
  RAM: 32 GB (Kingston HyperX 4x8gb)
  OS: Windows 10 Pro

Anything else that I should include that is not listed above, please let me know and I will provide it to you. Thank you for your time.

PS: Sorry for weird account name, accidentally used an old email that was saved.

 

[rhoban]

What about your CPU?
Such drops usually indicate the CPU being maxed out.

 

[xslayerx10]

What about your CPU?
Such drops usually indicate the CPU being maxed out.

CPU usage during my benchmarks on Heaven didn't exceed 30%
I also referred to the bottlenecking guide that is stickied on this forum, and the spreadsheet had shown that my CPU would not have bottlenecked them in any way.

 

[BurgerandChips66]

What PSU are you using? What are the specs?

Maybe power delivery is an issue.