Look at a couple more things and follow some logic.

Programs run in RAM. That means that if you have a lot of TSR (terminate and stay resident) programs running, your RAM is full and you are using swap space for your executable program. Thus when the program needs to make a call back to the memory page holding the program, you need to go back through your processor, back to the swap space on your hard drive, find and load what that call is asking for, and then come back through your processor toward your RAM. This is why IT nerds preach about having as much RAM available as possible. (If you are running XP you can only really utilize 3gb of RAM no matter how much your system says you have available. AVAILABLE and ACCESSIBLE are 2 very different terms.) Bottom line is to make as much RAM as possible available, so load nothing besides RB when you use it and test to see if that makes the problem go away.

Also, and you may already do this, click START ==> RUN and type in

%temp%

That will open your system temp folder. Delete as much as you can. (Anything in use will not delete. That is normal. Just get rid of all you can.) Your system refers back to those temp files and that slows your system down by wasting CPU cycles doing it. You RB cache of temp files will clear and reset every time you start the program. Save often and restart RB. As soon as you notice RB starting to be sluggish when you select anything (to change gain, for example), save your song and reboot.

As far as number of tracks, I have been as far as 23 tracks on one particular song that Rog had his students do "choir" vocals on. That song ended up with 2 lead vocal tracks, 6 backup vocal tracks from Rog, and 6 vocal tracks from me. 14 tracks for JUST vocals.

But bottom line, get back to computer basics for what you are seeing. This sounds like a computer performance issue more than software. Defrag will not help this. Think about what defrag does. It takes segmented files and makes them contiguous. Those files will load no matter what, and once they load, it no longer matters if they are fragmented or not. Defrag may speed up loading time by 2 milliseconds but means nothing after the loading is done. Most worthless utility out there, and one that techs at the level of Geek Squad who know nothing better will tell you is a fix for your problem. (DO NOT use Geek Squad. All they are trained to do is upsell. I set them up once and busted them but that's a whole other story.) You sound like you are having a system interrupt (an IRQ) that is "breaking in" on the CPU as it runs your RB process.

Just my dime.