[PD] glitches when moving between sub patches

[forwind]

Hi all,
        
At the moment I am attempting to refactor a patch. Part of this involves
moving alot of the exposed functionality down into sub patches. I have
noticed however after doing the patch work I get glitches when I open
and close the sub patches. The machine should have no problems being a
64bit 8 gig . The distribution is 64studio 2. Audio is handled by jack.
        
The limits.conf has :
        @audio - rtprio 99
        @audio - memlock 250000
        @audio - nice -10
        
the xwrapper.conf has:
        allowed_users=console
        nice_value=19  
        
And fstab has:
        shmfs           /dev/shm        shm     defaults        0
        0
        none            /tmp/jack       tmpfs   defaults        0
        0
        none            /mnt/ramfs      tmpfs   defaults        0
        0
        
The graphics card is a nvidia GEForce 8600 GT running under the nvidia
driver version 169.07.
         
I suspect this is what is causing the glitches but don't know how I can
stop it from 'getting in the way'. A last gasp effort could involve
raising the nice value even more which past 19 might be a bit extreme ?

Any ideas. There didn't seem to be any settings to optimise the graphics
card through the nvidia control panel.  
        
Best regards,
Conor