dannyjmusic
I think there was an update recently, maybe that's the reason ...the Tascam driver was up around 9ms round trip!
I thought ASIO for all was not supposed to be a good driver, but I gave it a shot anyway...seems to be working fine right now...we'll see :)

Cool. 9ms does seem a bit high if you were running your buffers @ 64kb.

Especially with USB 3.0

Congrats on your purchase. I almost bought the US 20X20 recently but ended up buying another acoustic guitar instead. My 18i20 is still going strong. Maybe next year? Then again the Focusrite Clarett interfaces look great too.

dannyjmusic
Especially with USB 3.0

Be aware that some audio devices perform poorly on USB 3. Have you tried a USB 2 port during your trouble shooting?

9 ms round-trip sounds about right with 64 samples with the US-20x20...there are USB safety buffers that add several milliseconds. FWIW that's about 4 ms more than Thunderbolt on a Mac, for a lot less bucks...in any event, for me 10 ms is the crucial dividing line for real-time playing. Playing guitar below 10 ms feels good; the feel becomes progressively worse about 10 ms. 
 
Also note that the US-20x20 uses class-compliant USB 3.0 drivers, i.e., it communicates directly with the host rather than through chipset drivers. I believe this is what makes it more or less independent of the chipset (remember that with Windows 7 and before, there wasn't native OS support for USB 3.0 so you needed to install a chipset driver for your USB 3.0 chipset). I don't know whether a custom driver could lower the latency further; that seems like a possibility. However the tradeoff might be some chipset incompatibility issues.

I'm liking the celesonic.  No latency issues at all.  I had the focusrite forte and was having all kinds of latency problems.  For $500 it's a no brainer, i.e. IF TASCAM SUPPORTS ITS PRODUCTS PAST ONE OR TWO YEARS!!  That's been my only deal with Tascam.  Spending money that goes down the drain.  I still remember gigastudio  haha.  Honestly, all Tascam has to do is give some reassurance that they're in it for the long haul.  Their sales would pick up.  I go into guitar center and other places, people roll their eyes at tascam. 

I think the main reason why TASCAM is using class-compliant drivers is not to be dependent on chipset drivers that are subject to change without notice. 

Is the USB-3 option on these babies still not available in Win 7?