Nuendo live 64bit CL3

Hi, just took delivery of two pcs of Cl3
and are preparing them for a tour right now.
My problem:
I have got everything working fine, latest
drivers and software for everything.
The connection to the Rio 3224 is all set up,and in
Daisy chain mode i have a pc with Nuendo live connected
to the secundary dante on the desk, i can record just fine.
But when i try to send the recorded audio back
from the pc to the Cl3 it cracks and pops big big time!!
Tried to tweak Asio latency, buffer size, slimmed the OS
and all the usual audio fixxes, and im running
out of ideas… Prob in short: cannot make virtual soundcheck
by running audio flow From pc To cl3
Help please…

Hi again!
The solution to my problem as described in first post,
was a to slow a computer, so no blame should fall on Steinberg or Yamaha for this.
BUT, the computer i tried it with was a Asus with C2D 3.0 GHz and WDC disc, win7 and 4gigs of ram.
I personally think that should do the job, but no.
I switched to a Asus with an Intel I7 and WDC disc win7 and 8gigs of ram, and now the playback functions brilliant.
So my advice to future users of CL3 and Nuendo live is: Overshoot the system demands as much as you can, and everybody will be happy!
Cheers…Its friday