Slow glRenderMode ( GL_SELECT ) Performance in Recent Graphics Drivers

[RAY16]

The problem is detailed on this page: http://www.cs.usyd.edu.au/~tapted/slow_glselect.html

Apparently this problem has been happening with every driver after 7.11. I haven't tried them myself, but there are numbers on the site. I'm not even sure if the 7.11's support my HD3850. Either way, I ran the testing utility on my 3850 with the 8.3's and I can confirm that it effects me as well.

[N] Using hardware accelleration
Reshaping to 800 x 600
[N] Calling SDL_SetVideoMode(800, 600, 32, 0x20000017)
120000 squares render in 154ms
120000 squares render in 120ms
120000 squares render in 119ms
120000 squares render in 118ms
120000 squares select in 4386ms
120000 squares render in 116ms
120000 squares select in 4378ms
120000 squares render in 116ms
120000 squares select in 4351ms
120000 squares render in 115ms
120000 squares select in 4360ms
120000 squares render in 118ms
120000 squares render in 117ms

I thought Blender felt like it was running a little slower since I upgraded to this 3850 from my 6800GT, I guess it wasn't just my imagination.

I would submit this to ATi myself, but I'm having trouble registering on the support site. I'll try again later, but I'd appreciate it if somebody could test it and submit it to ATi.

[Sound_Card]

Thanks, I will email this to someone.

[TheNGTV]

One note on the 8.3s:

They have broken OpenGL in workstation apps. Next Limit's Maxwell Render and Realflow apps, both which use the same OpenGL method, crash at startup. Vista app, used to run.

I might have to remod my card to OGL if that persists.

[sireric]

GL_SELECT changed performance when we changed OGL code base. It's certainly on the "needs" improvement list, but less than other features, since it's not that frequently used. But there are improvements coming within the next few drivers.

BTW, the 3850 is not able to run the legacy OGL like the x1k series -- But everyone's been switched to the new code base, which is the performance difference seen.

[RAY16]

Just a little update on this...

Well, sireric said that performance improvements were coming in the next few drivers, and it looks like the 8.5's have brought a nice boost in performance for GL_SELECT.

My results with the 8.5's:

[N] Using hardware accelleration
Reshaping to 800 x 600
[N] Calling SDL_SetVideoMode(800, 600, 32, 0x20000017)
120000 squares render in 152ms
120000 squares render in 137ms
120000 squares render in 129ms
120000 squares render in 175ms
120000 squares select in 483ms
120000 squares render in 122ms
120000 squares render in 177ms
120000 squares render in 197ms
120000 squares render in 129ms
120000 squares render in 146ms
120000 squares select in 451ms
120000 squares render in 117ms
120000 squares select in 459ms
120000 squares render in 121ms
120000 squares render in 173ms

A post on the BlenderArtists.org forum with other reports: http://blenderartists.org/forum/showthread.php?t=125217

So yes, there has definitely been a huge jump in GL_SELECT performance. Still not as fast as it was pre-7.11's, but far better than the 4000+ times in the 7.11-8.4 drivers. Hopefully they'll eventually be able to get it back down to the double digits like it was in pre-7.11 drivers, but this will do for now.

Thank you ATi!

[spike700]

Originally Posted by sireric

GL_SELECT changed performance when we changed OGL code base. It's certainly on the "needs" improvement list, but less than other features, since it's not that frequently used. But there are improvements coming within the next few drivers.

BTW, the 3850 is not able to run the legacy OGL like the x1k series -- But everyone's been switched to the new code base, which is the performance difference seen.

Is any of the legacy support going to be added back into the drivers? either OGL or DX? the missing calls has broken a LOT of old games

[sireric]

Originally Posted by spike700

Is any of the legacy support going to be added back into the drivers? either OGL or DX? the missing calls has broken a LOT of old games

I don't know of anything missing in DX. As for OpenGL, it's been added, but I don't know individual schedule. Which particular extension were you thinking about.

[spike700]

wasn't really thinking of any in particular mainly curious if they would be put back in.

As for the the DX stuff, there is something wrong with some of the DX6 calls, a number of older games display corruption on the 3800's.

Another curiosity regarding the lack of 16bit dithering, would it be possible for the drivers to force 16bit to be rendered to a 32bit render target? It would fix the color banding.

[Argoon1981]

I was one that reported this to ATI, Wings3D the 3D app that i use after the 7.10 drivers became slow as hell i couldn't select anything in it or the app would slow massively, to this day i only used the 7.10 drivers because of this i will try the 8.5 but if i don't see a significant improvement in this i will stay with the 7.10.

I have a x1900 XT but if this is not resolved it will certanly be my last ATI card as wings3D is very important to me more them any new game. Nvidia also had problems with W3D but now they work very well, i hope ATI does the same.

[kohan69]

Originally Posted by spike700

wasn't really thinking of any in particular mainly curious if they would be put back in.

As for the the DX stuff, there is something wrong with some of the DX6 calls, a number of older games display corruption on the 3800's.

Another curiosity regarding the lack of 16bit dithering, would it be possible for the drivers to force 16bit to be rendered to a 32bit render target? It would fix the color banding.

I can confirm the dithering issue and extreme slowdowns on a Radeon 3870 running catalyst 8.5 on XP 32bit SP3 (and SP2)

[spike700]

Originally Posted by kohan69

I can confirm the dithering issue and extreme slowdowns on a Radeon 3870 running catalyst 8.5 on XP 32bit SP3 (and SP2)

The lack of dithering isn't really a bug/issue, it was a design decision. Neither the 3800s nor NV's 8000 series are capable of 16bit dithering AFAIK.

I can't say that I have experienced any slow downs on the games that work, but a number of dx6 games display graphical corruption rendering them completely unplayable.