Is the audiotracker you speak of the one as supplied with the FDI FA8 Package?
I have a feeling my red (working)Steinberg one is a 20bit. And the soundpool 24bit.
Things sounded a lot nicer through Flextracker with the Soundpool.
Also I have never been able to Optically connect the fdi to my Sony MDS JE510 (mini disc). I wasn't able to work out whether there were problems with the outputted level or ? as i have no software to directly control this.
any clues apart from NVDI / CT60 etc. on making Cubase work faster, some times it has a terrible habit of slurring.