Hi

Doing some comparisons of PCs as preparation to buying a new laptop, I've
noticed some unexpectedly large differences in Squeak's graphics
performance.

I narrowed it down to the speed of DisplayScreen>>forceToScreen:

For example, running the following within an identical 3.7 image on four
different systems gave the per-loop timings listed below.

   Time millisecondsToRun: [
     1000 timesRepeat: [ Display forceToScreen: Display boundingBox ] ]

Toshiba dynabook SS LX/190 DK    [laptop]
1.6 GHz Pentium M 730
NVIDIA GeForce Go 6200 TE 64M / 6600 TE 128M
6.0ms

NEC LaVie LR 700/9    [laptop]
1.6 GHz Pentium
ATI Mobility Radeon 9600 series
8.1ms

Dell Dimension 8200   [large desktop]
2 GHz Pentium 4
NVIDIA GeForce2 GTS
19.0ms

Dell Inspiron 8000    [chunky laptop]
1 GHz Pentium III
(not sure about the driver)
33.2ms


Processor zorch alone doesn't explain it; is the secret in the display
drivers?  Or something to do with video memory?  Or something that could
be tweaked on a given computer?

Personally I don't rely on massive display speed, but when working with
lots of debug output going into the Transcript the difference is certainly
dramatic  :-)

Many thanks

Aran
--
Aran Lunzer
Meme Media Laboratory
Hokkaido University
Sapporo, Japan