performance problems with ATI Radeon r300

Thu Jul 9 05:42:02 BST 2009

Felix Miata <mrmazda at earthlink.net> posted 4A4CD62A.2020908 at earthlink.net,
excerpted below, on  Thu, 02 Jul 2009 11:45:46 -0400:

> I find this thread a bit hard to believe. Are there really people so
> naive as to believe a 5+ year old machine should be able to competently
> provide full KDE4 (Vista-style 3D) bling? I would expect only a
> Vista-competent (no more than ~9 months older than Vista) machine to
> produce acceptable KDE4 bling. My Radeon is rv380 (X600), and I wouldn't
> expect it to do well without all the bling turned off.

It should be able to do at least as well as the older KDE3 technology 
does on the same hardware, with the same level of effects, on the same 
xorg config.

Here, kde 3.5 (3.5.10) is my working desktop.  kde 4.2 (4.2.4) is my 
frustration desktop.  One (but by no means the only one) of the reasons 
is that 2-D only EXA accel, transparency-only effects (no fade, no drop-
shadow), are still so much slower than the exact same effects level on 
kde 3.5 works with virtually no slow-down (as compared to no effects), 
where on 4.2, it's slow and buggy, to the point kde tries to turn it off 
occasionally.

More details:  

General platform:  Gentoo/~amd64, both kde 3.5.10 and 4.2.4 installed.  
Older original dual socket Opteron 2xx style mobo (Tyan s2885), dual 
maxed out 2.8 GHz dual-core Opteron 290 CPUs, 8 gigs RAM.  4-spindle SATA 
based md/kernel RAID, RAID-6 main system, RAID-0 cache dirs, 4-way 
striped swap, /tmp on tmpfs.

Specific to the issue here: Older r200 based Radeon 92xx (for many years, 
the best graphics hardware one could buy to run with freedomware 
drivers), running dual 1920x1200 LCDs stacked for 1920x2400.  That's 
critical, as either the card or the driver limits OpenGL to 2048x2048, so 
the the bottom 352 px of the bottom monitor isn't OpenGL accelerated.  As 
a result, kde 4.2 won't enable OpenGL (even on the upper 2048 px) 
effects.  OK, I can accept that.

However, there are two specific issues:

1) KDE 4 provides no indication of what effects actually work with 
XRender, and which require OpenGL.  One would think they'd disable (dim 
out and make them unselectable) the OpenGL required effects in XRender 
mode, but they don't.  Thus, one has to go trying each one to see if it 
actually does what it says on the tin, and if it doesn't work, one is 
still left wondering whether it's that it requires OpenGL, or whether 
there's something else disabling it (maybe one hit the wrong keys trying 
to invoke it, maybe it conflicts with another enabled effect, maybe kde 
isn't seeing the key for some reason, etc).

This one is a major usability bug that frankly, should have been fixed 
before a release the PR said was ready for the general public.  It's easy 
enough.  KDE already detects whether the system can safely enable OpenGL 
mode and disables it if it needs to.  Why doesn't it disable OpenGL 
requiring effects in the GUI at the same time?  That's a beta level quirk 
and I'm a power user that enjoys testing beta level software, but it 
should have never made it into a release intended for general public 
usage.

2) Even with the same effects settings as 3.5, kde 4.2 is DOG SLOW, 
seconds to respond to active window changes, etc, where the response is 
essentially instant in 3.5, to the point kde tries to disable the effects 
sometimes.

Again, if it can be done in 3.5 without noticeable slowdowns at all (at 
least with EXA enabled instead of XAA), what's the problem with 4.2?  The 
hardware is obviously capable, or I'd not have already been using the 
exact same effects (transparency, no drop-shadows or fading) on kde 3.5 
for years already!

And in 3.5, those effects were supposed to be bolted on and thus not 
supposed to be at peak efficiency, while in 4.x, they're supposed to be 
integrated, and therefore should run FASTER!

Anyway, I'll probably be upgrading to an r500 based card one of these 
days.  The board is late AGP with PCI-X, no PCI-E, so unfortunately the 
cards cost more and the x1950 (rv570/r580) I'm looking at is still 
running $150, unfortunately.  And that's hard to come up with in this 
economy.  I may end up getting an earlier x1650 (rv530/rv560) instead, 
for $70 or so IIRC.  (The r5xx chips are the highest with full xorg/
kernel freedomware driver support ATM, the r6xx/r7xx chips are newer, but 
don't have full xorg freedomware driver support yet, and the r5xx chips 
are likely as good or better for AGP anyway, if they even have AGP based 
r6xx/r7xx hd series cards at all.)  KDE4 should work on them with full 
OpenGL effects, which will be nice.  

But that still doesn't answer the question of why if kde 3.5 can manage 
an effect with virtually no slowdown, the same effect is dog slow on kde 
4.2, or why the effects selection doesn't disable the opengl choices when 
opengl is disabled.  For this and other reasons, kde4 remains 
"substantially broken" for my usage, at least thru 4.2.4, and my kde4 
desktop remains my "frustration desktop" while my kde3 desktop is my 
"working desktop".  Oh, well...

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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