I find using onboard video (most Mobo's now a day support dual DVI) is less the headache.
DAW set ups are not like gaming computers, you don't need a great video card.
Even though the GT-730 isn't a great video card to begin with, your really not gaining anything by using it vs using onboard video.

rontarrant
I've gone around a few times with this one and found the best way to deal with nVidia cards is to:

• do a clean install every time
  • under Options, select "Custom",
  • in "Custom Install Options,"
    • click the box next to "Perform a clean installation" (under the boxed area)
    •  deselect HD Audio Drivers (do this as well as disabling them in System Manager)
    • deselect 3D Vision Driver

That should stop most of the interference and here's a guide.
 
You may still have to mess around with background vs. foreground tasks here's another guide for that.
 
Hope this helps.

Thank you for the suggestions, Ron. Your time and effort is very much appreciated.
 
I followed your advice to a T, even with one of the first drivers compatible with this card (following Brando's input), but alas, the problems remained.

The quickest and easiest workaround that I've found so far is to just temporarily disable the driver for the card in Device Manager while working in Sonar. The only things I seem to lose visually are the Aero window transparencies and one or two other minor theme customizations (and before anyone asks, yes, I tried disabling the transparency setting itself; no change). Also, the Now Time cursor tracks a little less smoothly during playback. But at least the audio seems to play without missing a beat (no pun intended).

I've been thinking about jumping on the Platinum bandwagon for the lifetime updates. I don't see what would make a difference, and I won't get my hopes up, but it'd be lovely if the card played nicer with the new version.
 
 

chuckebaby
I find using onboard video (most Mobo's now a day support dual DVI) is less the headache.
DAW set ups are not like gaming computers, you don't need a great video card.
Even though the GT-730 isn't a great video card to begin with, your really not gaining anything by using it vs using onboard video.

 
Well, like I was getting at in a previous post, I needed the upgrade for another program (an art program that requires OpenGL, which my onboard graphics did not support). It wasn't a modification geared toward Sonar.

And the card scores 7.0's out of 7.9 in the Win Experience Index, ranks decently enough in benchmark tests, and has positive ratings online, so it can't be all that bad. A couple of years outdated, sure, but nothing I'd call downright poor, especially not for my more truly poor budget :P

UPDATE:
 
So here's an odd twist to the conundrum...
 
As I was writing my last post, I had Sonar open in the background. After finishing the post, I switched back over to it (with Firefox still open) and hit play to find what?... Smooth playback. "Huh?" I asked myself as I cocked my head like a confused canine.
 
I proceeded to close Firefox, restarted Sonar, hit play, and... found the stuttering again. I tried opening a few random windows (Computer, My Documents, Notepad, etc.), and tested Sonar again. No change. So, I opened up a new, blank FF window (with the wifi disconnected, even), hit play once more, and lo and behold, glitch-free audio...
 
I'm stumped. What can be gleaned from this? The only thing I can think of is maybe it's some kind of memory issue, like the video card for some reason needs more to do in able to run smoothly in Sonar?... But how would that make any sense?
 
Opening a browser window is even easier than disabling the driver as a workaround, but I'd love to know WHY it's having the effect that it is.
 
Any theories?...
 

My laptop's card starts working notably (it has a rather loud fan) when I have even a background tab with YouTube in it. Possibly, your browser "activates" your card? And it's in low power/sleep mode using Sonar?

I had a similar problem and I solved it successfully. Generally, it is known problem. Just set the maximum perfomance in the power settings:

Sanderxpander
My laptop's card starts working notably (it has a rather loud fan) when I have even a background tab with YouTube in it. Possibly, your browser "activates" your card? And it's in low power/sleep mode using Sonar?

 
Hmmm, interesting... I'll have to check if there's a way to adjust the card's "power mode" while using Sonar.
 
 

cool
I had a similar problem and I solved it successfully. Generally, it is known problem. Just set the maximum perfomance in the power settings:

 
Thanks for the suggestion, cool, but I've already had it set that way to help with some browser issues I was experiencing. I'll try applying the setting specifically for Sonar's program, but since it's already set this way under "Global Settings", I don't see that it will likely make a difference.

Something else to consider is IRQ assignment sharing on your motherboard.  You had an empty PCIEx16 slot until you added the nVidia card.
 
The easiest way to look at these shared hardware assignments is to open Device Manager | View | Resources by Connection.  Expand the row with IRQ and scroll down until you see the PCI devices listed. The numbers in parens are the IRQ assignments.  If any devices have the same number, they are sharing interrupts.
 
Windows has permitted IRQ sharing for years, but if two devices don't get along, could be trouble.  My mobo manual breaks out the sharing by slots and controllers, so hopefully I won't do something dumb like put a high bandwidth controller in a PCIEx slot that shares with another busy device

Everything seems to check out ok for me on that front, abacab, but thanks all the same for the tip.

I have used nothing BUT Nvidea Graphics cards since forever. But I don't update to every new driver. I only update the Manufacturers drivers , Like MSi, or gigabit. Right now I have an MSI Geforce Nvidea 650 Ti Boost. Unless I see a change that is OK for all manufacturers. I mean 20 years and no issues....So I don't believe it's hit and miss. Unless I am lucky enough to HIT every time. Only times I had some issues was updating a driver without checking it out. I am running 2 versions behind on my cards drivers according to Nvidea. MSI I am up to date.

I have also used only Nvidia cards without any issues.  Currently on an MSI GTX560ti with latest drivers as of 31 Aug 2016.  One thing I always do is disable all adjust the graphics for best performance in the system properties. (Turn off menu animations, turn off areo , etc)