Are you using wav or decompressing wma ?
If wma try decompressing the RealTracks/RealDrum of the style you are using.
In bb\data\ there should be a decompress.exe/zip
if you put that in a RealTrack folder and run it, not in the root as it will do all.
Try that.

Now those RT RD folders move/backup elsewhere,
now create a RAM drive and copy those folders to it, you can delete all the wma out of the RAM drive folders.
Create a symbolic folder link back in the RealTracks and Drums folders pointing to them on the RAM drive.
So now it will read the wav files direct from RAM and generate them into RAM.
Try that and see what results you get.

https://www.raymond.cc/blog/12-ram-disk-software-benchmarked-for-fastest-read-and-write-speed/
https://www.ghacks.net/2017/04/03/the-best-free-ramdisk-programs-for-windows/

http://www.softpedia.com/get/PORTABLE-SOFTWARE/System/System-Enhancements/Portable-Symbolic-Link-Creator.shtml