I just wanted to say I have been having this same issue.
I run BI as a service and this issue generally started with BI versions within the past year or less.
As EDCK indicated, while BI is running, the entire PC is slow and laggy. Even programs and processes not related to BI in any way. Even File Explorer. Even delayed typing sometimes as he mentioned. I load task manager and performance tab to watch the CPU graph, and IT will even stop/pause for a sec then continue.
And as EDCK also mentioned, once the BI service is stopped, ALL these issues go away and the PC works fine.
I have also tried all the sub-stream settings, GPU settings, etc. My main BI disk is a RAID5 volume with qty 4 - 4TB drives. I've tried different settings for that too (cache mode, etc.).
I checked windows event logs. Tried using perfmon (performance monitor) with many different kinds of counters. Hardware appears fine. tried latest updates/drivers/etc.
I don't know what else to check either.
My hardware is...
Asus TUF Z370-PRO Gaming MB
Intel Core i5-8400
16GB RAM
Nvidia GeForce GTX 1050
OS/boot drive: 256GB SSD, BI DB on here
BI video disk: RAID5 qty4 - 4TB drives, using built-in MB RAID: Intel Optane
this PC is dedicated for BI in my basement, I only RDP (remote dekstop) it when needed.
I use the web UI3 all the time.
Ok if anyone has any ideas or does find anything out, it would be great to know.
Thank you.
-Spock