FPS Reduction in GZDoom 2.2.0

[Starscream2]

I've noticed that a few areas in my mods have been running slower on the new version of GZDoom (2.2.0) compared to how they did previously (2.1.1, etc). This reduction in FPS seems to vary from around 10 to 15, and sometimes more (there are times when the FPS has been improved, however). I know the new version of GZDoom added lots of new graphical features, and I have done the comparison with the immediately noticeable ones off.

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Winter's Fury MAP02
2.2.0: http://i.imgur.com/96LQtui.png
2.1.1: http://i.imgur.com/3ttradK.png

Winter's Fury MAP04A (Exact starting position)
2.2.0: http://i.imgur.com/lGKpLCc.png
2.1.1: http://i.imgur.com/9Du2BjU.png

Insanity Edged MAP01
2.2.0: http://i.imgur.com/AnUco56.png
2.1.1: http://i.imgur.com/lGZD9oR.png

Insanity Edged MAP02
2.2.0: http://i.imgur.com/7UwgB4q.png
2.1.1: http://i.imgur.com/bt8ukmF.png

Insanity Edged MAP03
2.2.0: http://i.imgur.com/7vSZzgj.png
2.1.1: http://i.imgur.com/aetdXMD.png

Is anyone able to tell me what is going on here? Is this permanent and something I will have to fix/deal with? Or is my hardware garbage?
I wasn't sure whether this counted as a bug or technical issue, so please move this topic if required.

Intel Core i5-3570K CPU @ 3.40GHz
16.0 GB RAM
NVIDIA GeForce GTX 670

[Rachael]

What happens when you run with "gl_renderbuffers false"?

[Starscream2]

Ah, turning gl_renderbuffers to false has restored them to their regular frame rates. So what exactly is going on here? What is gl_renderbuffers doing?

[dpJudas]

It provides the infrastructure to do shader based gamma correction (for windowed mode), multisampling and post processing effects.

[Starscream2]

Thank you for the info. What should I do about this then? Would it be best to tell people to set gl_renderbuffers to false if they are experiencing slowdowns while playing my mods? Is there an option to do so in the display settings that I have missed?

[Rachael]

Thank you for the info. What should I do about this then? Would it be best to tell people to set gl_renderbuffers to false if they are experiencing slowdowns while playing my mods?

You can suggest they try it. Ultimately it's an optional feature. But it saves to your config - you'll have to remind them to turn it back on if they want tonemaps/bloom/etc.

Is there an option to do so in the display settings that I have missed?

No, there currently is not. If you think there should be one, please do let us know, but it's ultimately up to Graf.

[Graf Zahl]

If you switch off gl_renderbuffers you'll lose a few features and a others will be downgraded.

Multisampling will be disabled and you will also fall back to the older invulnerability map code which has a few problems with additive translucency. The only map where this really caused a noticable FPS drop for me is Frozen Time, which dipped from 53 fps to 48 fps when overlooking the entire level from the bridge, but the maps that push my system to the limits are so rare that overall the benefits outweigh the performance loss.

[Starscream2]

I see. That's unfortunate, but I understand. Thanks for your time.