Yes, I meant PM. I sent one for you to see if he's around and wants to weigh in on the thread.

Hi lifeismusic.
I have the same Tascam mixer as you, and let me say I have truly been impressed with it as both a mixer AND my audio interface.  (My brother has a $2500 interface that he swears sounds on par with mine...LOL)  So, hard to beat for around $300!
 
In my experience, I have never had any latency issues when using the Tascam driver.  My metronome works perfectly also.  I don't have any odd buffer settings either.... just stock Sonar X3. 
 
I am not at my studio and am on a friend's computer right now, but when I return, I'll look at some of my other settings and see if there's anything you might check.
 
Oh... never be afraid to ask for help in here! Someone is always willing to assist.  Believe me, I need my share of help!  LOL
 
More later.

Cool. Thanks, Tony. Maybe let her know what driver version you've got installed while you're at it.

Even though you may have many USB ports on your PC, you have only 2 or so usb hubs inside with multiple ports on each hub.
Each hub can only support the native USB bandwidth. 12Mb for USB 1.1, 480Mb for USB 2 and 5MGb for USB 3. The multiple ports connected to each hub share this bandwidth.
If you have several devices sharing the hub bandwidth with your Tascam, this may affect the latency. Try removing other unnecessary USB devices and also switching the Tascam to other ports.
 
Michael

gwen/Dave-  My Tascam driver is the one that came with the M-164UF, so it's old.  I'm still away from my studio and won't return till tomorrow.
 
(The M-164UF driver is available on the Tascam website.)
 
Tony

You guys are so great!  Thank you so much for being so helpful.  Even if I have to scrap the interface, I already love this community :)
 
Maybe I should try the original driver...  all I've used is the up-to-date (2.01) from the website.  It's the only one they have listed for my OS. 
What's really weird is I'm seeing this same delay on this computer, and another that I took 3 minutes to load the driver and the CEntrance latency test utility on.  It's really too bad -- this seems like an AWESOME recording interface, and I was very excited about it until I started trying to actually record and stumbled on my timing issues.  I just can't seem to find anything left to blame other than the fact that it was a used unit and might be defective :/  If the delay was consistent it would be any issue I could adjust for, but every time I click 'measure' in the utility, I get a range of values (just like my manual bounce-back test in sonar).   At the high latency setting in the control panel (512 sample buffer, 11.61ms ) I get back usually roughly 50ms, and sometimes 20, or anywhere in between -- or sometimes it'll be much higher, and even experience what seems to be an audio drop out.  The lower settings provide lower latencies, though the variability is still roughly proportional.   Sonar too sometimes has an audio dropout when I initially start recording, though the frequency seems to be unrelated to latency settings.   The same thing happens on both computers, or I'd be ordering a new one right now.
 
Oddly, this utility can't operate on the lowest (~1ms) latency setting, though all of the other programs do just fine.  My midi setup rocks ;)  so at least I get to have fun jamming out with all my new toys.  maybe i'll start doing some electronic stuff in FL for a while... heh
 
hey, still a good mixer for 150 bucks though :)  Maybe I should take the mixer to a friend's house and run the utility there before I go buying new equipment though.
 
-gwen

There isnt some kind of fancy setting somewhere that would have it automatically run a silent pingback every time recording starts and offset the cut by that much immediately after is there?  lol
 
 
PS:  Just to clarify for one of the replies, I have removed all USB devices other than my keyboard and mouse and tried many different ports.  Its definitely something I'll remember in the future because I shaved off some time, but it didn't begin to touch this problem :(
 
-gwen

Really strange. you should try to get your hand on that old driver release, and maybe also try to hunt up a PC with XP on it to test.  As I said before, I really can't imagine how something could be physically wrong with the hardware to cause added latency, unless maybe the USB port has electro-mechanical issues that are causing a ton of extra error-checking to occur or something like that.
 
Strange as it sounds, you might want to open up the interface, and unplug/replug any ribbon cables or other connectors to wipe off any oxidation, and maybe flush the USB port with a suitable spray cleaner. I can't tell you how many times I've fixed a malfunctioning device just by taking it apart and putting it back together with or without cleaning anything. and try another USB cable if you haven't already.
 
And are the ports USB 2.0? I gather there can be compatibility issues between USB 3 hubs and USB 2 devices.
 
 

Lifeismusic,
 
Some of the symptoms you describe sound to me like DPC latency issues, usually caused by drivers for other components on your system, such as networks. In addition to all the other good things that have been recommended and you have done, you may want to download and run LatencyMon, which will tell you if your system is suitable for processing real-time audio, and identify the drivers that cause the highest DPC latency, among other things.  If it detects unsuitably high DPC latency, you can try disabling the component whose driver is identified to see if that improves the issue.

All suggestion are welcome at this point, of course, but I have to say DPC latency seems an unlikely cause. First because the symptoms are the same on two machines, but moreover because if DPC latency were to approach or exceed (!) buffer processing time the symptom would be that the transport simply wouldn't run or would stop almost immediately due to the audio engine dropping out.