Probably nothing.

The "Brutal Doom" series of ZDoom/GZDoom mods are notorious for having very poorly written scripts (ACS, DECORATE, you name it) that really trip up the VM overhead in GZDoom itself.

GZDoom's primary present shaders are also very large and already put a huge overhead on what is essentially simplistic graphics by comparison. But, even if you had the top of the line RTX cards or whatever, and with the best CPU with very high (THE HIGHEST YOU CAN GET) single threaded instructions per cycle, at the end of the day the GZDoom source ports are not properly multi-threaded anywhere. The CPU is always going to be the bottleneck and getting things to run smoothly ends up requiring modders to C A R E F U L L Y profile their work to make sure there is little to no VM overhead.

Slaughterwads will always cause significant VM overhead even if you're just playing things "vanilla" because of the sheer amount of thinkers involved.

Also in regards to "complex maps" the more sectors a map has, the more overhead it causes. And this overhead will exponentially increase if "lineportals" are involved. Looking directly up or down in GZDoom will cause the source port to traverse the BSP tree twice producing even more CPU overhead.

DracoNihil wrote on 2024-05-16, 06:57:

Probably nothing.

Judging by the single digit performance on this map you are probably right, I doubt that it would improve drastically if I used a CPU like a Ryzen 5600X with 60% more single core speed. What I don't understand is that some people claim that it's playable on their core i7 7700 with GTX 1060 but that CPU is not that much better than my E3-1230. Not sure what to think now unless someone tried GZDoom with BD on a map like Eviternity 2 Myriad and it was playable. Haven't seen such a video so far so it doesn't seem plausible. I'll probably just godmode it until most of the monsters kill each other and continue normally when the framerate recovers, no other options unfortunately. Thanks anyway.

Vipachei wrote on 2024-05-16, 08:18:

What I don't understand is that some people claim that it's playable on their core i7 7700 with GTX 1060 but that CPU is not that much better than my E3-1230. Not sure what to think now unless someone tried GZDoom with BD on a map like Eviternity 2 Myriad and it was playable.

Well, I'm gaming on a Intel NUC (model NUC6i7kyk) which is a i7 Skylake with Iris Pro 580 graphics; it runs things like my girlfriend's "Codename: DEMOLITIONIST" and also "Hideous Destructor" just fine with 60 FPS up until I start CPU bottlenecking because of the aforementioned VM overhead.

If you can run something like "Total Chaos" at 60 FPS then your GPU is fine, it's really just the CPU being bottlenecked by too much stuff going on inside GZDoom's VM. Too many thinkers, too many sectors, etc.

DracoNihil wrote on 2024-05-16, 10:44:

If you can run something like "Total Chaos" at 60 FPS then your GPU is fine, it's really just the CPU being bottlenecked by too much stuff going on inside GZDoom's VM. Too many thinkers, too many sectors, etc.

"Skipping" ahead with godmode worked and the rest of the Eviternity 2 maps had decent FPS so I got lucky. I'll do the same with other map packs from now on because it's still better than not being able to play at all. I know I should just abandon BD altogether but it's too much fun.

That Xeon is a Sandy Bridge-era chip topping out at 3.7 GHz, so it's about on par with the old i5-3470 that I replaced back in 2018. I upgraded to a a Ryzen 2600X then and the performance gain in games was substantial (although I don't play Brutal Doom), and I noticed even more performance gains going to a 3700X and then a 5800X. I appreciate how people on Vogons are a group that likes to keep old hardware in use for a long time, but pretty much any desktop CPU (aside from the cheapest Celeron or Pentium-branded systems) made in the past five years is going to be substantially faster than that old Xeon.

You can somewhat improve your performance with Nvidia cards. They perform much better in OpenGL. And yeah, GZdoom has minimal benefit over multi-threaded performance or new instruction sets. Add even less optimized Brutal Doom on top of that and you get that. For Doom specifically, you can MUCH better performance with PrBoom+ on complex maps, but it's not compatible with Brutal Doom.

MadMac_5 wrote on 2024-05-16, 21:17:

I appreciate how people on Vogons are a group that likes to keep old hardware in use for a long time, but pretty much any desktop CPU (aside from the cheapest Celeron or Pentium-branded systems) made in the past five years is going to be substantially faster than that old Xeon.

That's very true and I'd probably have a better rig if I did regular gaming but I don't. No need for an upgrade when 98% of you time is spent watching old TV shows, Youtube and browsing forums. As Draconihil pointed out the problem with BD is poor coding and a better CPU might not offer substantially better performance at all so I'd end up buying a new CPU (board/RAM) for nothing. I would absolutely reconsider if someone showed me a video of playing BD on a huge map with tons of monsters at playable levels but I've yet to see one. It probably doesn't exist.
Ironically I'm able to play a 2020 game like Doom Eternal on my 2013 GPU and 2011 CPU but fail playing Doom. 🤣
Well, that's life.

The Serpent Rider wrote on 2024-05-16, 22:28:

you can MUCH better performance with PrBoom+ on complex maps, but it's not compatible with Brutal Doom.

Yes, PrBOOM was the first thing I investigated when I started having issues but people said it's an entirely different thing unfortunately.

Prboom+ doesn't have decades of baggage to support competing standards of extending game logic (among other things). OTOH, not being able to run Brutal Doom is a plus for a myriad of reasons...