experiences with dual-dvi on ATI Radeon cards / NV-cards

Daniel Kasak dkasak at nusconsulting.com.au
Thu Apr 12 16:05:25 PDT 2007

Martin Schuhmacher wrote:

> Hello,
> at the moment I'm using a Matrox G550 on PCIe Card.
> Its not that good on 2D. It seems, the closed driver is ugly.
> So, a new Card is to come... I have the choice between ATI and
> NVidia. At the moment i saw the "ATI Radeon X1650 PRO".

Avoid ATI cards like the plague.

ATI's drivers are substandard compared to both nVidia's drivers, and the 
open-source drivers. I've been stupid enough to buy a number of ATI 
cards, and ATI's drivers:

- cause regular lockups
- don't support anywhere near the feature list of nVidia's drivers or 
the open-source Radeon drivers
- have pathetic XRENDER performance ( an order of magnitude slower in my 
testing )
- has had broken xv support for over a year
- is not in active development

This last point may raise some eyebrows. Seriously though, ATI have 
added precisely nothing over the past year, apart from another dodgy 
motif-looking control panel. They've somehow managed to break things 
along the way though ( r200 support, xv, software suspend, custom 
modelines ). The mind boggles.

If you must buy an ATI, for God's sake, get one that's supported by the 
r300 driver ( luckily mine is ).

> What about the ati driver performance on 2d ?

Very, very bad. ATI's 2D performance compared to the open-source Radeon 
driver's performance is quite bad, even when you just compare it to XAA 
performance. But the Radeon driver also supports EXA, and this make the 
difference in performance between the 2 even wider. Admittedly, the r300 
driver only has sketchy EXA support at the moment, but at least you can 
imagine this situation improving.

I did some benchmarking ages ago on my Apple Powerbook ( 1Ghz G4 with a 
64MB Radeon 9250 ) with Enlightenment-0.17 with the XRENDER engine. 
Unfortunately I don't have the figures sitting around at the moment ( I 
posted them to the Enlightenment list, so I can track them down if you 
really want ), but I can say this: the performance was very good ... ie 
quite fluid, low CPU usage, etc. When I do exactly the same benchmark on 
my current system ( a 2.2Ghz Turion with a 256MB Radeon X700 Mobility ), 
my CPU usage goes to 100% and I get about 2 frames per second. It's 
absolutely pathetic, and quite clearly outclassed by much older 
hardware, with much better drivers.

Other people have benchmarked and actually kept the details around. For 
example, check out bug #7 at ATI's 'unofficial' bugzilla:

 From the above bug report:

> Radeon X1400 Mobility, fglrx 8.33.6, Core 2 Duo T7400:
> 240000 reps @   0.0285 msec ( 35000.0/sec)
> Radeon 7500 Mobility, X.org radeon 6.6.3, Pentium-M 1.3 Ghz:
> 3200000 reps @   0.0019 msec (534000.0/sec)
> Geforce 6600, Nvidia 97.46, Athlon X2 4200+:
> 24000000 reps @   0.0003 msec (3990000.0/sec)
> Yes, you read that correctly, the Radeon X1400 is 15x slower than the (now 
> obsolete) Radeon 7500, and 114x slower than the (similarly priced) Geforce 
> 6600. To buy new hardware only to find that it's exponentially slower than the 
> old hardware at the most basic of tasks is insulting. There shouldn't be any 
> problem with making the X1400 *at least* as fast as the 7500, and preferably, 
> competitive with it's similarly priced competition.
> Unless this situation is rectified (either by the fglrx drivers being fixed, 
> or documentation being released so that open source drivers can be developed), 
> I will not buy any more ATI hardware, simply because it is embarrassingly 
> slow.

> Since the bad experiences with the matrox, is it known to work
> with x.org 7.0 on dual dvi ?

You should have no problem setting this up, whatever card you get. I 
have my current Radeon working with pseudo-xinerama mode with MergedFB. 
ATI's drivers have dual-head support, but I've never used it, so I can't 
really comment on it. nVidia's cards also have dual-head support.

Also keep in mind the Intel graphics chipsets now have excellent support.

Daniel Kasak
IT Developer
NUS Consulting Group
Level 5, 77 Pacific Highway
North Sydney, NSW, Australia 2060
T: (+61) 2 9922-7676 / F: (+61) 2 9922 7989
email: dkasak at nusconsulting.com.au
website: http://www.nusconsulting.com.au
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