RDX-PRO Not using full system

[Ryland Chin]

Just recently built a new PC at work to be able to use for proxies when we finish a shoot before going into post. Specifically using RCX because of the prores support on windows, however when we ran our first proxy test it wasn't seeming to be as fast as it should be. It was running a 25 minute clip in about 32 minutes, its still pretty fast but when I went to see the performance tab in task manager our CPU only had a load of 10% on it and our GPU's (2 1080ti's in SLI) only had 2% on each. It seems that RCX is holding back on the system. To compare when brought into Davinci or Premiere or Media Encorder it would run the same clip in about 8-10 minutes. Granted these tests were not 1 for 1 as the other programs don't have Prores support and so they were exporting DNxHR, but its basically the same thing.

Anyone have the same issues and know how to fix it so that RCX will actually take a chunk out of the PC?

System Specs:

Windows 10
Threadripper 1950X
2 1080ti in SLI
64gb Ram
500gb M.2 SSD
2 500gb Sata SSD
Asus Rog Zenith Extreme MOBO

Thanks!