Here's some things I came across so far that may be of interest :

First a good quirk: I upped my athlon64x2 from 2.0GHz to 2.2GHz and changed my RAM timing from 5-5-5-15 to 4-4-4-12, and somehow my rendering speed increased by almost 30%.  I redid the test many times to be sure.  Strange but good.

Second quirk: If you ever try to save a corrupt object to a presets folder it can wipe out that entire preset folder, and you won't know it until it happens.  Lucky I had a backup of that objects folder.

Third quirk:  When manipulating a complex grouped model, suddenly one of the subgroups can shift position unexpectedly and for no apperent reason.  Lucky I had a backup of my model.

Fourth quirk:  Some scenes would continually crash in a terrible way right in the middle of manipulation. When I changed the names of imported objects to simpler names, the crashes went away.  It appears that long, complex object names caused the crashes, but I'm still not 100% sure.

The bottom line... Bryce away but be careful!

First one(good quirk, lol), you should test your system stability overnight running something after you overclock, especialy with ram as it can cause HDD corruption on some systems. Wouldn't want Bryce to fail in the middle of a 12 hour render.

Second, this sounds scary, can anyone else confirm? 

Agree with third, you do have to be carefull of moving objects and/or clicking in the window or something will shift, even after you switch views etc... I try to lock everything Im not using, but in a complex model this can be a problem.

Fourth, I did read something on DAZ forums and here about that, but I thought it got fixed in B6... Maybe 6.1 update.

As to the corrupt object bringing down the whole basket of fruits, could be very true.  I had a whole file of Bryce 5,0 objects completely gone to waist...  One object at a time....
 they still showed in the window but when clicked on,,, wam,,,,  error message..

First quirk - Sure. Your new cpu was 10% faster to start with, then you might want to check, there might be other differences in the cpu's; L1, L2 cache size, FSB, etc. Together they can have a huge affect on actual cpu speeds.

Second quirk - As tom also voiced this is not a problem only in Bruce 6.0, it's most likely the caulprit of such Library "dissapearances" with users for many years (imo)

Third quirk - Yup, I have had that happen. I haven't ran across it since that B6 update, but the quirk was very random to begin with, so it doesn't mean that bug is gone yet. The B6.1 patch is coming.

Fourth quirk - Never have had that problem, but I have heard of it from various users over the years, with earlier versions of Bryce. Members have mentioned it also with naming objects inside of Bryce with very long names (in the Attributes window). Stick to shorter names I guess. shrug

5th qiurk - If you have Bryce6 and any version of Vue installed on the same machine and try to run them simultaneously (and at the same time) , your head will explode !

6th quirk-  starts a high resolution HDRI 100% quality render- HAL computer speaks; "Im sorry [insert name], I can't do that",...LOL.

Seriously though, Bryce 6 needs a FAQ somewhere for these things(quirks).

Third; definitely.  Drove me mad during:

http://www.renderosity.com/mod/gallery/index.php?image_id=1375487

The building group on the right would keep jumping forward after I had adjusted something.  Not enough to notice the first half-dozen times, but the overnight renders were always screwed up; took me a few days to realise it was happening.  "Save, save, save" became my mantra......