Problems with Rewire!!

Hi everyone.
This is my first post on the forum. I've been reading it for a good while now and have read some wicked information that has really helped, so a big THANKS to all. :clap:
I'm having a problem trying to use Reason with Sx 2. The computer i use is a Mac G5 dual 2 GHz with 2 GB RAM. The sound card is the Nuendo Digi96/52.
I open SX and activate all the Reason rewire channels i'm using. I then open Reason and get a drum pattern going with the Redrum. When i press stop and return to the begginning and press start again, there's a brief pause and a stutter before the track starts to play normally. It then cuts out altogether for a short time before returning.
I also get clicks and pops in the audio but can remove these by going to Device set-up, VST multitrack, Expert and then un-tick Multi processing, but should i have to do this? I've tried to tick and un-tick the lower latency and Adjust for Record Latency boxes which has not solved the problem. Please can anyone help?

geb the same problems myself at times. I always thought is was coz my processers pretty weak @1.7gig and the CPU was being overworked.