I am thinking if you have your buffers set too low, its not the driver or Sonar that is the issue.  Your computer can't process the information fast enough (disk read/write, CPU cycles, etc.)  I can only get my buffers down to 128 but the round trip latency is still acceptable at less than 10 (might be 7 or something like that, I don't really remember).\ but that is because I am running an i5 with a regular 7200 rpm drive.
 
I guess the bottom line is, what latency do you need to successfully record?  For me, as long as I am less than 10ms, I am fine (its probably higher than that, but 10 is a good round number.)  To put it in perspective, that is the equivalent of a live situation where the bassist is standing 10 feet away from the kick drum.

Yeah but when you set the buffers too low, you're supposed to get dropouts and crackles etc, not maxed out meters or no sound etc.

I play guitar through amp sims, and when the latency is too high, I can feel the lag between the pick hitting the string (and the sound it makes) and the "amp" sound.

For me 8 ms RTL is good, but 5 or 6 is better. ;-)

The weird thing is, I could run at 64 sample buffers if I opened the song at 128 and then changed to 64
Now without the 64 bit engine it works fine? These newest drivers are very good.

jbraner
Yeah but when you set the buffers too low, you're supposed to get dropouts and crackles etc, not maxed out meters or no sound etc.

I play guitar through amp sims, and when the latency is too high, I can feel the lag between the pick hitting the string (and the sound it makes) and the "amp" sound.

For me 8 ms RTL is good, but 5 or 6 is better.

John is 100% right on this one.

Apparently I was wrong on my earlier post when speculating that nothing is happening to the 64 bit engine. Cake just announced a fix for 2017.07

Apparently I was wrong on my earlier post when speculating that nothing is happening to the 64 bit engine. Cake just announced a fix for 2017.07

I'm really glad I checked the "pop and maxed out meters" threads ;-)
That's how I found out they're doing something about it - but let's see *what* they do ;-)
They're talking about completely different problems than what we see - but they must all be related somehow.
 
I think I'll just skip the 64 bit engine anyway...

I agree maxed meter and no sound is different that what I'd expect from buffers too low.  I think I have had 64 bit precision engine turned off since the initial issues with it back in X3.  I have never had a reason to turn it back on.

jbraner
There are some other threads about pops, maxed out meters, no sound, VST3 plugs, 64 bit engine etc, and some of these symptoms are what I see when I have my buffers set too low.
 
I've always blamed the MOTU drivers for this, since things work fine when I set the buffers right. Also with these newest drivers, I was having problems on some files when using buffers = 64, but I could change the MOTU buffers to 128, and it worked fine - then when I changed back down to 64, it continued working fine.
 
I've been working with MOTU support, and not much happening.
 
Now the breakthrough! I disabled the 64 bit engine in Preferences -> Driver settings - and voila!! All my files load fine at 64/48 and 64/16! I still can't use buffers = 32, but if I disable all plugins, it's fine. So I think this is a SONAR (with some VST3 plugins) problem after all. I think the bakers are on to it (according to the other threads) so in the meantime - I'm finished scratching my head.
 
I think I can finally say that these newest drivers are really good. ;-)

Updated the main system to 2017.06 (build 23.6.0.24) today and immediately ran into this problem despite not having encountered it before. So this 100% a Sonar 64 bit engine problem of the latest release. Thanks, John, for figuring this out!
 
This must be some strange initialization bug because it's 100% reproducible i.e. I get garbled playback when starting Sonar with 64 bit engine checked, but unchecking as well as re-checking fixes it ...

It's weird though - because I've had this problem for quite a while, and never thought about the 64 bit engine...

I am noticing a couple of oddities.
 
When I have my buffers set to 1024 and I try to play iTunes I get pops and clicks.  Dropping the  buffers to 128 fixes the problem.  Not sure if this is normal or not.
 
Occasionally, I will get distortion when trying to record and I have to switch the sample rate and then switch it back (usually from 128 to 256 and then back again, although I have switch to 64 and back to 128 also.)  This usually causes the interface to disconnect from Sonar and reconnect.

I'm seeing this sometimes too. I think some combinations of buffers/offset aren't great together.
 
I find that when the offset is 16 or 64 I'm OK, so
 
64/16 OK
64/48 OK
but if I need more CPU juice
128/16 OK
128/48 OK
 
Offsets of 24 and 32 (I'm not sure about 64) do what you say - sometimes.
 

@jbraner I think I have my offset buffers set to 48 (never changed them).  I haven't checked the 64 bit engine, but I have had that turned off since no could ever explain to me what it did and there were problems with back in X2 or X3.  I will have to see if its back on or not.