Noel Borthwick [Cakewalk]
Please be careful about disabling the high definition audio device on the computer since it will surely disable all onboard audio for other apps and could adversely affect apps that rely on it.

 
You can always enable it again...besides, if I'm running Sonar, all I care about is performance with Sonar.
 

I think Craig listed "High Definition Audio Controller" which has a different name from HD audio device..
I don't think you can generalize that any onboard audio device will cause latency problems. Normally onboard audio is a completely different path from an external audio device. So if you are using ASIO it shouldn't be impacted by onboard audio. 

 
I wouldn't think so, but there's no question that if I disable these system devices, my ASIO interfaces work with lower latencies than was possible before, sometimes dramatically so - and the system is more stable. This has happened with both Roland and TASCAM interfaces on two different computers (one desktop, one laptop) so it doesn't seem like a corner case.
 
The main reason I posted this is because what I was seeing seemed too good to be true, so I was hoping other people would give it a try as it's a reversible procedure. Nothing needs to be uninstalled, only disabled. 
 
Maybe it doesn't relate to the audio, but rather, with stopping a process that reduces system efficiency? 

So, with this disabled, I can change the Asio driver in Preferences to a lower value?  Is that what we are saying?

Noel Borthwick [Cakewalk]
Are you using ASIO or WDM for your main audio interface? Also is your onboard audio device an NVidia audio device?

At least on the laptop, this relates only to ASIO; the "High Definition Audio Controller" is listed as coming from Microsoft, so I presume it's a different deal from the ATI driver on my desktop. I was reluctant to disable it at first because it was a Microsoft device, but I figured I could always re-enable it. However disabling it nonetheless appears to improve ASIO performance, although not as much as disabling the ATI driver did on the desktop.
 
If I choose WDM, the TASCAM interface connected to the laptop "sticks" at 256 samples and changing latency in the TASCAM control panel makes no difference. I can still hear system sounds, audio from YouTube, etc. I don't have to go into the Control Panel Sound option and set a different default or anything. I'll check out WDM on the desktop later tonight.
 
Regardless, I was not able to track guitar with the lowest latency setting on the US-366 before disabling the High Definition Audio Controller driver. It's still "on the edge" but it's useable. 
 
So I may be doing something wrong, but I can't argue with the results. And with the V-Studio/desktop, being able to play back power-hungry Sonar projects at 64 samples instead of 256 is really cool...
 
But this wouldn't be the first time I ended up doing something "right" by doing something "wrong" 

konradh
So, with this disabled, I can change the Asio driver in Preferences to a lower value?  Is that what we are saying?

Maybe, maybe not. I'm reporting on my experience, although it seems quite a few others are noticing the same results. I can most definitely change the ASIO driver setting for much lower latency and get away with it...and the system is more stable, too.
 
Of course with your computer, all bets are off.... 

Craig, you are consistently full of interesting surprises. Thanks. I will try this since latency is such a **** on my laptop.

CakeAlexS 
I disable the nvidia audio driver myself. I believe it's what drives the audio via a HDMI connection so you can get sound through the speakers of your connected TV set.

Anderton Do you have to disable it under System Devices or could you disable under Sound, Video, and Game Controllers? Did you notice a performance hit when it was enabled? I'm curious whether this is AMD-specific or has broader implications.

Well in theory improved some latency in LatencyMon and in my view improved stability.
 
To be clear I disable the "High Definition Audio Controller" under system devices, and the NVidia HD sound drivers (even better I try not to install them via custom install). Please note I have two ASIO sound devices and have disabled onboard audio on the motherboard BIOS.
 
Cheers...

**Updated Information**
 
I have been in dialog with Noel (Noel, please correct me if any of the following does not interpret what you've said properly) and he does not think the Microsoft High Definition Audio Controller in System Devices is the culprit, but only the ATI device. He also thinks this might have little to do with audio per se, but rather that the ATI device slows down performance in general, which of course would affect latency (in which case it's quite a slowdown, to say the least!).
 
However, here's how the Microsoft High Definition Audio Controller became part of my scenario. The AMD device could not be disabled originally, only uninstalled and I didn't want to do anything that wasn't reversible. The only way to disable the AMD Device was if I disabled the High Definition Audio Controller first; I've just left the Microsoft HD Audio Controller disabled too because everything was working so well, but based on Noel's comments, I'll re-enable that - I'm pretty sure that I can still leave the AMD device disabled once it has been disabled, but re-enable the Microsoft HD Audio Controller. If the performance increase continues, that will point at the AMD device and not the Microsoft one.
 
Therefore for laptops, if all you have is the Microsoft High Definition Audio Controller and not some custom graphics device, it's probably worth leaving it enabled. Although I have noticed an improvement on the laptop here, after more testing it's much smaller than it appeared at first. As soon as I kicked in a heavy distortion algorithm on the TH2, it tilted the latency back to unacceptable. So the bottom line ended up that in either case, the very lowest latency setting could not be counted on for reliable operation, but the low latency setting could. Given Noel's concern that disable the Microsoft High Definition Audio Controller could trigger the Law of Unintended Consequences, it's probably worth keeping as is. 
 
Regardless, there is no doubt that in my system, something is causing a substantial, dramatic improvement and disabling the AMD High Definition Audio Device seems to be the key. I'll continue to follow up and see if the Microsoft High Definition Audio Controller has a role in this that goes beyond just making it possible to disable the ATI device, but I have to say once more that being able to go from 256 samples or crashes as a way of life to 64 samples and no crashes is a huge deal to me!! Given how many other people on the forum have experienced similar crash scenarios (freeze/motorboating/can't stop with Task Manager/reboot required), and how many have nVidia and ATI graphics boards in their sigs, if this can be nailed down it could change the quality of life for Sonar users as much as it has changed mine.
 
Meanwhile, any of these changes I've mentioned are all reversible, so feel free to experiment and report back with your findings.

I suggest downloading recently released latencymon V6, start it up and look at the processes and drivers tabs.
Under the drivers tab if you sort by DPC count/highest execution columns it should give you some idea...
 
Also update motherboard BIOS and chipset drivers.
 
Cheers...

If only you could find away around the latency issues of my laptops nvidia graphics driver

Gee Whiz, I haven't moved my sample buffer setting from 64 on my DAW since they day it arrived 2 years ago. I'd like to use a 32 sample buffer but MOTU arbitrarily took that choice away when they finalized the x64 drivers.
 
That DAW wouldn't have lasted a day if it couldn't do 64 samples straight out of the cardboard box and then hold steady while I mixed with my favorite reverbs, limiters, Kontakt instruments and soft synths.
 
It's crazy to think about what some people will put up with.
 
 
 
 
 
 
 
 
 
BTW, Jim R at Studio Cat, and Scott at ADK, have reasonable rates for over the phone consultation. It can be a great way to benefit from their years of experience and expertise and ensure that you may enjoy your DAW at its full potential.