In cakewalk 8.5, when recording audio OR midi, the time counter and the vertical moving line time indicator is so jumpy that it only updates about twice a second.  But it displays smoothly on earlier versions of sonar I have loaded (versions 2.2 and 4) using the same soundcard (m-audio usb) and bit rate (16).  

Surely version 8.5 isn't so much more resource intensive than the earlier versions that my system can't keep the visual indicators updated?

Turn off Scroll Lock on your keyboard. 

The scroll lock made no difference :( 

Try the Pause key.

If system resources are close to exhaustion, SONAR will reduce the frequency of screen updates in order to reserve more CPU cycles for the audio stream. You may find that a project with fewer tracks/effects doesn't exhibit this behavior, or that you can avoid it by raising your buffer sizes and/or freezing tracks.

I had to use an older 2004 laptop to do some remote recording and this is the behavior you get when using a under powered computer. After recording it would take almost 2 minutes to update the wave drawings. This does not have any effect on the recording but makes working on the machine impossible. So I don't use it for editing, just recording. 
The specs were P4 2.4 Mhz, 1.5 Gigs of RAM 7200 RPM HD, So what you are seeing is normal when using a older computer. I had stripped it down to bare bones with 18 background processes running. But that the best you'll get out of old technology. 
Computers are cheap, go buy a better one. 

Thanks everybody (esp bristol_jonesey) ...hitting the pause key fixed it :)

Apparently whatever the pause toggles is a newer default key binding that wasn't on sonar 2 or 4.

I'm curious though... does sonar 8.5 use up more resources than sonar 2 in that I would need a faster computer to do what sonar 2 does smoothly?

Glad that worked for you Justin.

Hitting the Pause key puts sonar into a sort of conservation mode and devotes more power to processing than screen redraws, much like Bitflipper described above.

8.5 has a LOT more going on than version 2 ever had, so it's safe to assume it's using more resources.

So, to answer your question, you need to list your entire system specs of your current machine - CPU, RAM OS etc. Everything you can think of. Hard drive(s), graphics card, interface/soundcard