SPEC NOTES:
The ARM chip used in the 5500 was the StrongARM. This CPU was developed by DEC with an instruction set licensed from ARM.
When DEC merged with Compaq, Intel bought DEC's semiconductor unit (including the StrongARM).
Subsequently, Intel upgraded the StrongARM line, and renamed it to XScale.
[Edited. Original from Clive in forum[s]... (I do like the original "Comapaq" though)]
The PXA250 has a "cache" problem, so its use is disabled. Some claim that the cache isn't all that useful anyway. Others claim great speed improvements with PXA255 w/ working cache. YMMV
The 6000 specs are not verified (07/MAR/2004)
Reports that new[er] 5600s purchased through Amazon have been received with PXA255.
OVERCLOCK:
pdaXrom overclocking speed chart (thanks to foxdie for image), see ZUG thread.

http://www.inboost.com/pc-boost/cpu-booster.html -- overclock warning
http://news.com.com/2009-1040_3-253289.html -- overclock warning
http://www.viewsonic.com/products/pocket_pc_pocketpcv35.htm -- overclock warning
Resolution Comparison:
Resolution Comparison (thanks to rev for image)

CREDITS / THANKS (TO) / SUGGESTIONS / CORRECTIONS :
Stubear
http://www.c-guys.net -- sdio
http://www.zaurususergroup.com/forums/index.php?showtopic=510&hl=sdio&st=60 -- sdio