One of our GL driver engineers is looking into this report.
Here are a few initial observations.
I ran the application with Crimson 16.9.2 on a windows 10 x64 machine with an RX480 + i7-6700K and was getting around ~54 FPS.
What version of the driver and what OS are you running ?
I was also able to capture performance with CodeXL and PerfStudio if ran GSDumpGUI.exe with the following command line arguments.
E:\Work\AMD\pcsx2\bin\plugins\GSdx32-SSE2.dll E:\Work\AMD\Community\perf-case.7z\gsdx_20160924182111.gs GSReplay -1
The obvious hotspots here included.
I will try a few more configurations and let you know what else I find.
Just to elaborate slightly on this (as I am one of the developers for PCSX2), this performance drop is consistent across the entire AMD range, regardless of computer specs.
OpenGL performance is usually roughly half that seen on DX11 using the same card/setup.
On Nvidia cards the performance of OpenGL vs Dx11 is about the same, sometimes it is 1-2% slower in OpenGL, but generally is the same speed.
So there is certainly an issue with the driver, one of our guys who works with making hardware for a living, also works on GSDX, said the OpenGL driver seems very single threaded, where Nvidia have a multithreaded driver for OpenGL, this wasn't obvious until he enabled the multithreaded support on GSDX when initialising OpenGL, that is when the gap between the card manufacturers appeared.
Is there any update on this at all?
One of our developers found an optimization to the OpenGL Program Pipeline implementation. It should get rolled into a release soon.
This was in Octoboer. Still nothing.
Almost a year later, I managed to find out even another testcase.
Aforementioned AMD systems can only get ~3, ~20 and ~60 fps in each of the tests respectively (basically no matter the GPU)
The nvidia smartphone-sized PC can reach 6 (7 with multi-thread switch), 45 and 105 fps instead.
bin.zip 789.3 KB
Up given these days engineers seem keen.