Is efb access slower on OpenGL?

MonadoBoy · 01-06-2018, 02:46 AM #1

I was doing some testing of various games on OpenGL vs Direct3d, and I found something interesting and was curious to see if I was having a hardware problem or if this is normal. I was testing Mario galaxy on 3d3 and it was running full speed. Using the same settings on Opengl I was getting anywhere between a 5 and 20 fps loss depending on where I was in game. I believe it has something to do with efb access, but I'm not sure. If it helps I was using a gtx 1070 and my processor is a i7-7700. Is efb access slower on opengl than it is on d3d?

**DJBarry004** · 01-06-2018, 04:43 AM #2

That´s odd since GL is faster in NVidia´s GPUs (unless you´re using Hybrid Ubershaders).

MonadoBoy · (This post was last modified: 01-06-2018, 08:31 AM by MonadoBoy.)

(01-06-2018, 04:43 AM)DJBarry004 Wrote: That´s odd since GL is faster in NVidia´s GPUs (unless you´re using Hybrid Ubershaders).

I was using hybrid ubershaders. I'll test it again without it.

Edit* I'm still getting a 5-20fps frame loss without hybrid ubershaders on.
it's most likely the efb access to cpu option. If I checkmark the efb skip option I get full speed, but can't fire starbits. Its weird though, I get full speed using direct3d, even with efb access to cpu.

**degasus** · 01-09-2018, 01:08 AM #4

You may try to enforce the "high power mode" in your GPU driver configuration. NVIDIA often detects us as "idle" and downclock the GPU. In fact, it is idle for 90% of the time, but we need the result as soon as possible.

MonadoBoy · 01-09-2018, 08:36 AM #5

(01-09-2018, 01:08 AM)degasus Wrote: You may try to enforce the "high power mode" in your GPU driver configuration. NVIDIA often detects us as "idle" and downclock the GPU. In fact, it is idle for 90% of the time, but we need the result as soon as possible.

I do that for dolphin. My global setting is adaptive, but for dolphin it's maximum performance, same with all my games.

Stenzek · 01-11-2018, 04:26 PM #6

Depending on the game, Vulkan may give you the best performance for CPU EFB access, based on differing implementations behind the scenes. If the game's access has high spatial locality, and only touches a few pixels, OpenGL will likely be faster. If it touches a few pixels across the entire screen, Vulkan will be faster. D3D is likely slower than both if it touches more than a few pixels. At some point we're hoping to unify all these implementations.