Conditions:
High Resolution Displays
All MacMini models
Sound Glitches
3d Glitches
Graphical glitches

Firstly, if you are using 2048x1152 there will be serious graphical glitches and crashes when using 3d or composition. This is apparently a known issue. Be sure to set your screen blanker to a lower resolution, such as 1280x1024 or your system will hang outright when blankers turn on.

Condition: General graphical/computational stuttering and sound stuttering
This is more than likelly caused by graphical data in vram being swapped with system ram.

Solution:
1. Turn off 'enhanced display' for all of your screens. This vastly reduces VRAM usage.
2. Set your ambient desktop background to a solid colour.
3. Turn off graphical backgrounds for individual ambient windows
4. Turn off graphical backgrounds for MUI windows
5. You may also set your screenmode to 16bit colour to further reduce vram usage by 50%

Notes:
They key to remember is that you don not want vram being filled and swapped by high-color large bitmap graphics. Whenever a vram<->ram swap occurs, the whole system will lock for a moment causing all sorts of bizarre effects.

An alternative to disabling all eye candy is to run at a very low resolution. It's a tradeoff.

Be aware that OWB is very VRAM intensive. Opening multiple tabs then swtiching between applications can cause a lot of stuttering especially if you have a lot going on as far as eye candy.

I'm running at 2048x1152 32Bit and am now using the aforementioned settings. My experience has improved vastly. No more audio stutters and 1-2 second lockups. Aminet radio now seems to work fine too.

Hope this helps other MacMini users.

ALSO NOTE:
A number of MCC classes are super buggy and will cause all sorts of crashes/lockups! Tell your software vendors to please use builtin classes where possible to avoid these issues!

[ Edited by Jason on 2010/5/4 3:32 ]

[ Edited by Jason on 2010/5/4 4:34 ]

What model of monitor do you use for displaying 2048 x 1152 image?

[ Edited by Krashan on 2010/5/4 8:57 ]

Point 1 implies point 3. There's no need to change buffering settings if Enhanced Display is off. Also, using 16 bit screens will reduce vram usage by 50% :)

Krashan:
Samsung SyncMaster 2343BW LCD
2048x1152 is the highest resolution available without dual-link DVI, or so I've heard.

jacadcaps:
Updated original post.

Will the 2048x1152 bugs someday be fixed?

[ Edited by Jason on 2010/5/4 4:35 ]

Use a 8 bit IFF ILBM or 8 bit grayscale PNG images as wallpapers, takes the same amount of memory like in single colour. Mode needs to be Titled (even if it is fullscreen image). This way I spare ~7MB on a 1680x1050 24Bit screen.