Ive been noticing this lately, as Im working on another album.
As a track records, the VU meters, timecode(s) and waveform preview start to bog down. By the end of the ~3min song, they only update about once a second. Anyone else notice this?
 

Seeing this again all the time (X3d) and figured I'd reboot this old thread. Has anyone else seen this?
 
In fact when I go to record a track and it records for about a minute, it slows down by the end of the 3 min track and updating is grindingly slooooooooooooooooooow.
Further, the STOP button completely disappears (so I have to hit PLAY to STOP transport/record)
 
My buffer settings were 256, so maybe i'll up it to 512.

I get this from time to time, cant figure it out but a reboot of the PC resolves the issue and since it only happens rarely it doesnt bother me too much.
 
Could be any number of things I guess, AV running, The Video card(s) working overtime on something else, Windows Update, Buffer settings (as you stated)...My theory is that the memory on the video card(s) isnt being released properly from another process.
 
 

have you tried emptying the picture cache ?
sounds like an update issue possible whats being loaded in to ram, a video card issue, up date your drivers.
and empty the cache man.

+1 for emptying the Picture Cache folder first before doing anything else.  That simple step seems to fix many of my issues.  Panu's Duckbar program has a command that will do that for you. Then start looking into video issues.  

Thanks for all the replies. I'll try everything listed here.
 
Its important to note that everything moving or drawing in Sonar slows down including the Bars/Beats/clock, VU meters, and drawing of the actual waveform. The audio records perfectly fine.

I'm having to highlight all tracks, right click, recompute associated audio files upon opening to get it to co-operate...

If you deleted/cleared your pic cache, then please list how much room is on your dedicated audio drive and what kind of effects are in this project. Also see if its happening on just this project. This will rule allot of things out
 
It could be that there is a plugin that is doing this or that your hard drive is too full.
 
I do want to add that its not your Anti virus program. 15 years ago AV programs could effect the performance of your Programs, but that is not the case in Now (2008-2014)
 
Cj