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List:       kwin
Subject:    Re: List of gfx cards and how they work with KWin
From:       Lubos Lunak <l.lunak () suse ! cz>
Date:       2008-09-18 17:29:09
Message-ID: 200809181929.09123.l.lunak () suse ! cz
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On Thursday 18 of September 2008, Rivo Laks wrote:
> Ühel kenal päeval (neljapäev 18 september 2008) kirjutas Lubos Lunak:
> >  Also, looking at the list, it appears quite obvious that there is no
> > simple rule for selecting which cards should or should not have
> > compositing enabled by default (for example, GeForce4 4200 Go outperforms
> > GeForce 6200 by quite a lot in glxgears, and regardless of how bad
> > benchmark glxgears is, this should mean something). So, I'm open to
> > suggestions and good ideas about how we could handle this :).
>
> Not suprising actually. 6200 is a low-end card (as are e.g. 5200 and 7300),
> but 4200 is a mid-end one (in GeForce4 series, 4 digit numbers meant
> mid/high end cards and 3 digit ones were low end cards).

 Hmm ... might explain why the 6200 is fine with passive cooling :).

> For NVidia's GeForce 5-9 series, it might be possible to determine the
> card's speed by looking at the first two digits of the model number. Low
> end cards have 2nd digit lower than 5, so one possibility would be to
> enable compositing if
>   model[1] >= '5' || model[0] >= '7'
> (this assumes that for GeForce7 and up, even low-end cards are powerful
> enough. Not sure if that's the case).

 Actually all the GeForce cards I have are quite fine. Even the GeForce2 one 
is acceptable. I guess this all really depends on the user and their 
perception of the performance. I'm currently thinking about enabling it 
automatically for any ati/intel/nvidia card that has acceleration working 
(like we already do in CompositingPrefs).

> And in some cases, you might even want to look at card model/driver combo.
> E.g. my GeForce 9600 was slow as hell until I discovered some hidden
> settings (which are also listed somewhere at techbase). After changing
> those settings manually, everything works very fast. But I don't know when
> those "good values" will be the defaults...

 I'm afraid those are next to impossible to detect from KWin :-/. There is now 
also a check for detecting too bad performance, but that one just checks for 
three consecutive repaints taking more than 1 second, which can catch only 
really pathetic cases. And I have no idea how to detect just bad performance 
without occassionally triggering also when there will be only a higher system 
load.

-- 
Lubos Lunak
KDE developer
--------------------------------------------------------------
SUSE LINUX, s.r.o.   e-mail: l.lunak@suse.cz , l.lunak@kde.org
Lihovarska 1060/12   tel: +420 284 028 972
190 00 Prague 9      fax: +420 284 028 951
Czech Republic       http://www.suse.cz
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