Clicks When Recording In Dp4.12, No satisfying hardware/device settings Options

[zimpy]

Dear all,
this is my first posting, so please be gentle...

Upgraded from dp3 to dp4 on an imac g4 800mhz.
Recording voice with a usb-edirol-ua3d was fine in dp3.
But in dp4 noise appeared in recorded voices, with the same hardware/device settings as in dp3.

Messing around with buffers etc. has resulted in identifying two different kinds of noise:
'Clicks' every 5-15 seconds like a grain of sand on vinyl.
Little 'crackling' sounds, constantly, more so on top of parts with higher amplitude.
By playing with ALL the settings in 'Hardware' and 'Studio Configuration' I can either make the clicks or the crackling go away completely, but never the both of them.
Am I forgetting something, some settings somewhere, some good old trick, some preferences. Or am I to return to dp3 and OS9?

cheers,
zimpy

[zimpy]

Thanks Kaboom,

There's 64+256Mb, and with other apps like photoshop and (light) video-editing, I never had any memory-problems.
Hmm, there's not a way, like in OS9, to assign more memory to an application, is there?
Or you reckon 320Mb is not enough?
ciao