[o-info] MOI OSX Quadro FX 4500 issue reported on CCP4 BB

From: Alwyn Jones (alwyn@xray.bmc.uu.se)
Date: Tue Sep 19 2006 - 05:31:14 CDT


there is an email from James Stround on the ccp4 bulletin board  
concerning the fx4500. i don't know how many o users also monitor  
ccp4 but i thought some of you might not. here is a clipping from his  
email:

'We have a few dual core G5s with Invidia Quadro FX 4500's running OS  
X 10.4.7. Its a good combo and performance seems to be more or less  
worth the money (expensive, but high performance). However, I found a  
terribly insidious bug when running these cards under "thousands of  
colors" (16 bit)--a bit depth I had set arbitrarily, if I indeed ever  
consciously set it at all.'

in the Display System Preference applet, you can set the number of  
colours to millions, thousands or 256. if you use o, you should have  
this set to millions. o uses a graphics api called opengl, and is  
written to work in so-called RGB-mode. there is a clumsier  
alternative called colour index mode which is mainly of historical  
interest. according to his email, you'll get problems if you set  
colours to thousands. i don't know any graphics card that needs to be  
using anything other than RGB-mode. having said that, i remember that  
Stéphane Réty could fix a problem under XP with intel's built in  
graphics card where one of his solutions (the other was to downgrade  
the intel driver) was 'to run O in 256 colors mode'.

so under XP, running a program written for RGB-mode and millions of  
colours with a setting of less colours seems to be allowed. OSX,  
however, doesn't like it.

Alwyn Jones
alwyn@xray.bmc.uu.se
http://xray.bmc.uu.se/alwyn



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