Are there differences in accuracy between DX11 and OpenGL in Software mode?

[FaunoComLabirintite]

Honestly, I don't really care about running older games in higher resolutions, so I prefer running in SW mode, keeping things more accurate. I've been using OpenGl SW mode with Resident Evil Outbreak (it actually runs much better than HW mode for me, at least with OpenGL, managing 60+ fps, while HW mode drops bellow 50 right at the beginning of the game, even in native res) and today I've tried Silent Hill 2, but it has occasional drops to 56-57, even during cutscenes, that cause audio cracks and stutters. I've tried both with SW and HW mode, and the drops occur exactly at the same spots.

Considering I've seen people saying (well, writing, since we are on the internet) that Open GL is more accurate, I was wondering if that info is only valid for the HW modes. Since I prefer SW mode anyway, if DX11 SW mode is as accurate, I'd just use if for everything.

Oh, I'm using PCSX2 1.6 stable and an i7 6700hq laptop with a GTX 970m, 16 RAM. Perhaps a developer build would bring me better performance on OpenGL?

Edit: I've also tried with and without Automatic Game Fixes and with and without MTVU on, no improvement.

[RedDevilus]

SW mode for DX11 and OpenGL is the same. In 1.7 devbuild we combined those 2 choices to 1 entry. As said in the progress report https://pcsx2.net/296-q3-2020-progress-report.html (https://prnt.sc/vo3yg6).

1.7 did have alot of improvements for frametimings but some games just run bad due to emulation behaviour not done correctly, low specs or wrong settings.
You could test a build in a seperate folder and see for yourself.

[FaunoComLabirintite]

SW mode for DX11 and OpenGL is the same. In 1.7 devbuild we combined those 2 choices to 1 entry. As said in the progress report https://pcsx2.net/296-q3-2020-progress-report.html (https://prnt.sc/vo3yg6).

1.7 did have alot of improvements for frametimings but some games just run bad due to emulation behaviour not done correctly, low specs or wrong settings.
You could test a build in a seperate folder and see for yourself.

Hey again! Thanks for the quick reply.


So, I've done some testing using 1.7 rev 623-g37f145f6b in the idle cutscene from Silent Hill 2 Greatest Hits edition:

- Using 1.7  OGL = a bit better than in 1.6, with 2 frames dropped but only on one spot of the FMV (as soon as the "Silent Hill 2" logo appears).

- Using 1.7 SW = exactly the same as in OGL, at least in the cutscene (which I suppose doesn't use any kind of 3D rendering).

- Using 1.7 DX11 = no drops whatsoever in the cutscene.


I've also played a little bit in the forest path, at the very beginning of the game, and it didn't seem to have any drops with OGL or SW, but I didn't pay as much attention in the drops as I did in the cutscene test, so I might be wrong.


Am I correct to assume that the differences from DX11 SW and OGL SW in the frame drops (1.6, of course) are caused by the way they interact with the GPU? I mean, since nothing is being rendered by the GPU...


So, that probably means that the SW renderer in the latest builds is using an OGL frontend? Perhaps it would be a good idea to re-include the DX11 option, IDK, for cases like this, but this is just a suggestion for the future. I'll stick to 1.6 and DX11 SW, since it gives me more stable FPS while maintaining accuracy.


I've also noticed, like you said, that the frametimings are more stable in 1.7, usually fixed at 59.94.


Thanks again!

[RedDevilus]

I don't know your specs , besides having a separate SW mode isn't a good experience, maybe interesting to fill that spot with Vulkan perhaps in the future. Frame drops can range from a number of reasons though from the game to your PC.

[FaunoComLabirintite]

I don't know your specs , besides having a separate SW mode isn't a good experience, maybe interesting to fill that spot with Vulkan perhaps in the future. Frame drops can range from a number of reasons though from the game to your PC.

I see! In the case of DX11 vs OGL, both in software modes, shouldn't they have the same performance? I'm just curious, really.