AMD gpus

[Ian]

I know a few people have been complaining for the past few months that performance on AMD cards is poor with my current renderer. Well I couldn't really fix the issue since I didn't even have an AMD card. Anyway I currently have a WX-7100 pro card in my machine ... and yeah performance is absolutely ridiculous with it. And it's a fairly high end card. I'm obviously hitting some kind of bottle neck with these cards.

Will try and find out where the bottle neck is this week if I have enough time

[xbrunox]

Thanks Ian!

[anchounio]

Thank you !!

[Ian]

Well I found the bottle neck. What I thought was the bottle neck turned out to be not the bottle neck at all.
Totally bizarre problem. It is the frame buffer emulation that's slowing it down, but it turns out simply drawing the FBO as a texture to the back buffer absolutely annihilates the performance, which makes no sense at all. The FBO (frame buffer object) has 3 texture attachments which I guess is a little unusual but it shouldn't be a problem. If i blit the FBO to the back buffer performance is fine. Look at the comparison .. it's completely insane

Correct render path:
https://i.imgur.com/RTySusy.png

Look at the GPU usage here, and note the frame rate.

Simple blit to the back buffer:
https://i.imgur.com/xBQPsPP.png

I'll have to file a bug report with the AMD driver team ..

[model123]

Hello Ian

So far I think it was optimized for Geforce, but from now on will it be optimized for radeon?

[Ian]

It's not optimised for any card, unfortunately it just runs slow (very slow) on amd hardware. I filled a driver bug thing, so maybe in 1 year we'll hear back :p

[LeSpank]

Ian - thank you for looking in to this.

I hope you get something back from AMD. Keep us posted!

[model123]

I understand that thank you for your reply

[Ian]

I posted about it here: https://community.amd.com/thread/240094

Maybe i'll need to put together a sample application

[xbrunox]

Hi all

i've an old ati radeon 7970 that is equivalent to a modern Radeon R9 280X.

for me the problems depend from drivers.
if i Use the last version named adrenalin supermodel run very slow.
if i Use the old crimson version of the drivers supermodel runs very well.