Replacement PB Duo 270C active matrix screen?

[Marc Sira]

> > Are you sure of the 280c being faster than the 270c?  I had
> > supposed that the FPU in the 270c might more than make up for the 030-040
> > difference.
> 
> The 270c doesn't have a built in FPU. However you can take advantage of an
> FPU if you run the 270c in a DuoDock (FPU was optional in the original Dock
> and standard in the DuoDock II & DuoDock Plus).
> 
> The 270c uses a 68LC030 and the 280c uses a 68LC040. The LC 
> nomenclature is referring to a lack of FPU.

I'm not sure where you got that idea, but Paul is correct, and the 270c has
a built-in FPU (I used to run Infini-D on mine). It also has a 68030, not a
"68LC030" - I'm not certain that model even exists , but if it does it
refers to something other than the lack of an on-chip FPU, since the FPU is
external to the 68030 in any case.

In terms of actually answering the question, a 68[LC]040 is theoretically twice
as fast as a 68030 at integer ops. My experience is that the real-world
difference on a Mac is somewhat less than that, though this may partly reflect
the tendency to run a later OS version on a 68040. Between a Duo 280 and 270
you'll find that the 280 is somewhat appreciably faster most of the time and
considerably faster for integer-only number crunching, but vastly slower (or
simply impossible to use) for floating-point work. Since you're only likely to
actually need an FPU for things like non-realtime graphics rendering, you can
decide which would suit your needs better. Most Mac software never hits the
FPU, especially 68k stuff (since the presence of one is so hit-and-miss, and
failing to find it is usually a crashing matter on a stock OS).

-- 
Marc Sira		|	toh at victoria.tc.ca
If you can't play with words, what good are they?