Yeah, that’s all but unusable. Have you tried closing all other programs and background processes to rule out conflicts? Also if you are running an anti-virus software, try disabling and running TheBrain for a short period of time just to see if it makes a difference. If it’s being particularly aggressive on monitoring disk activity it could cause something like this. Basically rule out that another program is interfering.
I think they already asked you to make sure you have enough free HD Disk space. That could also cause slowness. I’m assuming the database is stored on an internal HD and not one attached to a USB port. Those are the obvious things to check for off the top of my head. Are you seeing slow behavior from any other programs or anything else that could indicate a problem with either the HD or memory? F.ex programs increasingly becoming unstable and crashing?