Brutal Doom Hell On Earth StarterPack for slower computers file

Yes. For older machines you should use gzdoom 2.4.0 (it's included on the ZIP)
If that doesn't work, try Zandronum, it's a bit older.
Test map16 first, that's the most demanding map in terms of framerate.

I just became aware of an issue gzdoom 2.4.0 has with 3D sectors (bridges and elevated platforms you can walk under)
Maybe it doesn't affect this map-pack, but if you have problems they work just fine in gzdoom 1.9.1 and zandronum (also 1.9.1)
gzdoom devs always ******* up

I try to make all these modifications without ever touching the map editor. Too much manual labor unfortunately, I can't afford to put hours into that.
For the same reason I was not able to optimize Winter's Fury (a map pack from 2006 that still runs like crap in some computers to this day)
SgtMark, as much as people love to jump on the hating bandwagon to hate him (but everyone uses bits of his scripts here and there, huh? consistency, people... consistency...) he did a great job of making huge wide open maps while keeping them optimized as much as possible, it could be much worse, he could simply not care as he had an i7 CPU at the time if I'm not mistaken, but he took the extra mile to making things smoothly.
Back to Winter's Fury, the main problem with it is that the maps mostly consist of long endless stretches of map with two major flaws:
1) Putting the entire map in the same vertical floor level. For anyone that knows the basics of Doom mapping that's a big no-no, and the main reason because the original Doom1 and Doom2 maps are the way they are, with multiple levels and such.
2) On top of that, the guy made wide open sections of the map connected most of the time by doors that stay open (they don't close back) or even worse by translucent laser barriers or whatever they're called. You should always divide sections of your map using doors to block vision. If doors are not enough to keep CPU usage low, you should divide sections of the map with corridors, two doors on this corridor ensures visibility is blocked and the engine is not doing overwork.
If the map authors themselves don't care, then there's little hope of optimizing it.
I'm trying to spread this information around in the hope that mod authors in the near future will learn and stop making these simple mistakes, which in turn gives them less work to maintain the mods. gzdoom devs are encouraging modders to use the wrong methods to do stuff (some of the Zdoom wiki articles even ommit older information to only show the new methods) and it's up to us to make noise about it and stop this trend before it gets worse. If you have a core i9 and a Doom mod is giving you slowdowns, then sorry, I have to break the news for you, you're doing something terribly wrong.

What kind of machine did you use?
=D

Did it work?
In what kind of machine?
=D

I don't have that old computer anymore, but I can do a few tests. Please give me an example of an area that suffers with severe slowdowns. I need to know the exact maps and which area I need to go in order to detect slowdown. (if you can make footage or screenshots, even better)

Map16 is still a problem, not much that I could do with that one.
What kind of machine you are running it? I was getting 20 FPS (playable) in a core2duo (2009) laptop

You can try this new technique. I just found this a few months ago, mindblowing because I was getting slowdowns even in the new machine.
Try downloading earlier versions of gzdoom that will run with older GPU's (or with no GPU at all, Intel Graphics, etc) like version 3.2.0 or 2.4.0 ... The trick is running the game in Vulkan mode (restart to apply) Vulkan will make use of your graphics card, not just CPU, very useful for big crowded areas. Try that.

Did it work? Awesome, have fun