If you can, add/replace as many HDDs with SSDs. That will vastly improve performance.
I have my machine set up as follows:
- SSD 500GB for OS
- SSD 1TB for docs
- SSD 1TB for media (source footage/final projects)
- SSD M.2 250GB for temp
Especially the latter is the fastest drive.
Next up is to have a fast enough video card and enough RAM.
What RAID level?
How is the RAID connected? Internal or External, if External what interface to your computer.