Lpc2000

I'm looking into using ARM so I'm a newbie.  I currently use a 
processor that is 16 bits 30MIPS capable.  So seeing that ARM is 32 
bits and 60 MIPS capable has me wanting.  I've read that real world is 
actually 52 MIPS (still above my baseline 30 MIPS).  But then I've seen 
where you have to run 1/4 speed out of FLASH.  So is the 52 MIPS number 
just running out of RAM?  I'll need most of my RAM for application so I 
want the program to stay in FLASH.  Does running out of FLASH mean 52/4 
for only 13 MIPS thruput.  I might as well stay with my current 
processor if so.  I might as well stop reading all of this ARM 
documentation if this is true.