Recently I've been hearing pops and clicks, also, and stuttering when manipulating plug-ins, etc., which was not happening upon initial upgrade to X3 from X2. However I did notice my I/O Buffers were also set to 256, which I must have done a long time ago for some reason, so I'm going back to 512 to try this out, since this is apparently the default values. 
Thanks, Craig and Scott for the info.
 
 

Thank you, Craig. As you know I had done some other things to stop the crackles, mostly freezing synths, which I've never had to do in the past, but this fix worked. Like EricDeluxe said, I'm running a 64-bit system so I just assumed I should have that box checked to take advantage of running 64-bit. So now I'm running 64-bit unchecked and 512 in the buffers and things seem to be good. I hope more users see this.

I often wondered about that guitar. When I saw that Gibson made that I thought it was overkill. If you ever do a cover of something with that guitar Craig I would love it if you would post a .bun file just to see what it's all about. I'll never be able to afford one.

If all I have is audio in a project (no Soft-synths or 3rd party FXs) I can still go down to 64 to record. Once I went to 48 and it seemed ok.

Ok thanx. Tried this but can't hear any difference.

From the help file :
 
●
I/O Buffer Size. This value determines the buffer characteristics for transfers to and from the disk. Changing this value does not affect audio latency, but will affect the disk throughput for audio tracks. The default setting is 128. A higher value causes more audio to be buffered from the disk ahead of the playback cursor. If you are hearing consistent dropouts/clicks in your audio and if your project contains high bit depth (32/64 bit) or high sample rate audio (88.2K or higher), it may be indicative of a too small I/O buffer size. If so, try a higher I/O buffer size like 256 or 512. If audio problems persist, reset to 128 and try a different remedy.

Also, if you are playing a large file, and using maximum latency, a too-small I/O buffer size may cause dropouts or crashes. Try increasing the buffer size by blocks of 128.

 

Guitarpima
I often wondered about that guitar. When I saw that Gibson made that I thought it was overkill. If you ever do a cover of something with that guitar Craig I would love it if you would post a .bun file just to see what it's all about. I'll never be able to afford one.

You could just buy a pickup (and breakout box) from this guy...
 
http://www.ubertar.com/hexaphonic/index.html

And I'm not sure but I think that if you are doing a specific search for that type of pickup the term is "hexaphonic" while "hex" seems to apply to MIDI pickups as well... but I'm not sure. I only mention this because when I went looking for that site I was getting a lot of MIDI pickup results. Adding "phonic" narrowed it down to the audio ones (although it seems that guy is one of the only dudes who produces/sells them). 
 
I also found a gearslutz thread talking about making your own but heck if I understand what they're on about...
 
http://www.gearslutz.com/...ckup-guitar-synth.html
 

I had a weird issue with my Fast Track Pro. I got terrible results in Sonar X3, lots of crackle and distortion, with a buffer of 512. When normally I kept it at 256. I was in a rush and had to increase it to 1024 to continue tracking. After fiddling with it, I found I could put it down to 128 (its minimum setting). I just had to increase it initially and then bring it back down. No idea what was up there.

Turning off 64-bit engine? Seems contradictory to the many posts that say to turn it on, or leave it on.
 
After all, it's probably a setting that doesn't even really matter.
 
I believe that for most situations, and possibly for 50% of the Sonar population, nVidia graphics cards are to blame for most, if not all, audio crackles and pops caused by latencies. It would be interesting to set up a poll (is that even possible?). I know that I am biased, and a little negative towards the topic, because I am one of the "50%" that's experiencing problems.