Hi: I just rebuilt my music PC so it is very fast.  I have the Intel i7-5820K, 3.3 GHz 6 core CPU, 32GB of DDR4, and a Crucial 1 TB SSD, which runs much faster than my prior HDD's.  I am using Focusrite's Scarlett 18o8 as my USB digital audio device.  When I play standalone synths, including my Cakewalk products, I have to leave the buffer time set on the Scarlett at between 1 and 3 msec, depending on the synth.  Even Uhe's Diva, which always broke up on me on a couple of prior reasonably fast but somewhat slower computers (I think that's been an ongoing problem for many with that VSTi, which I am so far using, instead of as a VSTi (due to the problem at the base of this question), as a standalone, by taking advantage of Hermann Seib's Savihost, which works tremendously by the way), sounds marvelous, and all the standalone synths sound just great at those low buffer settings.  It feels like I have no latency whatsoever.  If I go any higher than that, though, even just to 4 msec, they all sound just terrible, with dramatically broken up tone and a ridiculous increase in latency as the buffer size gets up around 8 msec.  I am not sure because it was the first time I used the Scarlett device, but it looked like it was set up at 10 msec buffer time as the default, so initially everything sounded terrible like that and it took a little time for me to recognize the buffer time was the problem and figure out how to change it in the GUI of the Scarlett, which was new to me.  I can put it this way, though.  If all I wanted to do was play standalone synths, I would be ecstatic with the setup as it is.  They sound just marvelous and it is as if I had no latency.  The problem, of course, is that I want to be able to play all my VSTi's without having to go through Hermann Seib's Savihost, and the obvious bigger reason is that I want to be able to record them on my DAW.
 
Now the problem is tied to my DAW.  I recently upgraded from Sonar X3 to Sonar Platinum, and I don't know whether the problem I have is tied to that specific version, because it is the only one I have used on this upgraded PC.  The problem is, when I go to Edit/Preferences/Audio and go to select my buffer time, the lowest it will allow is 10 msec.  As such, if I try to open any synth whatsoever, including the included Cakewalk synths, as a VST in the DAW, it has the same terrible sound that I got in the standalones at any higher buffer size than 3 msec.  It's totally unusable.  I can't believe that 10 msec is truly the lowest buffer time allowed in Sonar's best product, but some how it is currently set up to allow me to go no lower than that on the slider.  I even wonder if it is set up to take the buffer time from what is available in the DA device, which was unfortunately set to 10 msec when I first opened Sonar Platinum, but of course that could just be a coincidence.  Does anyone know how I can adjust the allowed buffer time downward.  I would truly like to be able to leave it set as low as 1 msec and see how it functions starting from there, but I am worried, because as it is, I will be entirely unable to use Sonar Platinum.

Hi. Do you use ASIO driver? If not, you should be. Do you have the latest drivers to your audio interface?
Best of luck.

You are using a Scarlett interface which has an ASIO driver. That Preferences buffer slider is not for ASIO and if it is available for tweaking then you are not using the ASIO driver (which is what you SHOULD be using).
 
You need to set up the interface properly on your system and within your Sonar Audio Device Preferences and use the Scarlett's software to set your buffers. Be sure you have the latest Focusrite drivers for the device.
 
FWIW I can nudge my Scarlett 18i6 settings down to about 3ms on very heavy projects for low latency tracking without any weirdness (this translates to about 7-12 roundtrip reported latency from Sonar which is not really noticeable). I crank it up for editing and mixing.
 
Also the Scarlett series aren't the ultra low latency type of devices like some of its far more expensive counterparts but they are super solid and for most purposes on a decent system will deliver excellent results while tracking or anything else. You do have to use the ASIO driver though. That's what it is there for.
 
Cheers.

I am sorry for the delay in response.  I've had some major distractions in other areas of life since I put this up.  
 
As it turned out, the problem was not with the DA interface, at all, but I had made the mistaken presumption that if I had an ASIO DA interface like the Focusrite Scarlett 18o8 set up, Sonar would recognize it and automatically set itself to use the ASIO drivers.  In fact, Focusrite does not label the audio driver for the 18o8 as an ASIO driver, for whatever reason, but it does have that capacity.  It turned out the problem was that Sonar defaults to the MME drivers (for whatever reason in this day and age!  I mean, who would be using Sonar Platinum and have nothing more than a PC sound card based on MME drivers???), and I simply had to go into Sonar's Edit\Preferences\Audio to the third page of that section to change the MME setting to ASIO, and then everything was beautiful.  I've never had such a fast synth PC.  I can't exceed 3 msec buffer time or I just get horrendous noise!
 
Thanks for the prompt responses, and I hope my delay in getting back was not felt harshly.

rsredden
It turned out the problem was that Sonar defaults to the MME drivers (for whatever reason in this day and age!  I mean, who would be using Sonar Platinum and have nothing more than a PC sound card based on MME drivers???)

Based on posts in this forum, you'll see quite a few people are using MME devices and sound cards. Usually the first post after they ask their question about why there's latency or synths sound distorted is "get a proper interface and use ASIO drivers - and not ASIO4ALL."

I'm sorry.  I certainly didn't mean to offend anyone by saying that.  I really haven't been on this forum much (actually I think this was the first time), so I haven't seen those discussions and I made another mistaken presumption.  
 
Oh, and ASIO4ALL!  That's another thing.  I've tried it a couple of times over the years when I had a DA interface melt-down and I was waiting for repair or a new device, and I don't think I could get it to work any better than a PC sound card.  It was absolutely useless.  What is it all about?  Does it actually work in any context?

I don't think anyone was offended, no worries there. FWIW ASIO4ALL is just a "wrapper" for the Windows drivers to make them look like ASIO, which can be helpful with laptops if you want to try to get a little lower latency with the internal sound card. It's a kludge, and sometimes it works fine...sometimes it doesn't. The biggest problem I've seen is that it can interfere with bona fide ASIO drivers installed on the same computer.

Okay.  Thanks.  I'm all set here.  Thanks for the word "kludge", as well, which is new to me.  It strikes me as pretty useful.
 
 

Glad it worked out for you