2.5D shooters oddly slow?

[Danfun64]

Hello again. Recently my good computer died out, so now I'm using my older computer. Still, does it make a difference with a game as old as Doom? Apparently... I tried running freedoom on odamex and it is very slow even at low res 800x600. SRB2 has the same problems. Even DarkXL, which isn't related to doom at all (except that it's also a 2.5D shooter) also has problems. The reason i say "2.5D" shooter is to differentiate with "true 3D" shooters like quake, half-life and the like (of course, there is no way I am getting portal 2 to run as nearly as smooth as my other computer...) but still. Why should 2.5D shooters run slow while obviously more graphically advanced shooters run fine?

Here's my CPU-Z report if that's helpful to anybody...

http://pastebin.com/7HDn4USq

[tempun]

odamex is slow b/c it uses a software renderer. don't know about darkxl but think that a lot of tricks are required to faithfully emulate software renderer.

[Blastfrog]

Huh, very strange. My best guess is that your CPU might be bogged down by a ton of background processes, and this is why they run slowly. 2.5D games are very dependent on the CPU for graphics rendering, whereas the 3D polygonal games are moreso dependent on the GPU, meaning that the processor is free to do more stuff.

[EarthQuake]

Are you by chance talking about the maximum framerate? Doom ran at a fixed 35 frames per second, which I guess could be perceived as "slow". Your only option in that case would be to download a source port that has the option to remove this. PrBoom (I think) and ZDoom do this, as well as many others.

[lucius]

The reason that DarkXL runs slowly is this: NVIDIA GeForce FX 5200. Unfortunately, DarkXL will use Shader Model 2 when available which performs very badly on that series of GPU's. The next release will also have a fixed function mode, which you'll be able to force if necessary, which should run significantly faster on the lower end GeForce FX GPU's.

[Maes]

Yeah, the CPU horsepower should not be a problem with a Pentium 4-class CPU (even with a horrible Celeron and 128KB of L2 cache...ugh) for any software rendered port at the resolution you mentioned. If you had a Pentium III-class CPU then yeah, you'd have a real problem keeping even a steady 35 FPS at all times with that resolution using a software renderer.

However the amound of data that needs to be passed around is really a lot, and with such a small cache, it's easy to trash it to oblivion if you also have a fuckton of processes. Get rid of smiley central or whatever crap is running in the BG and then we're talking.

As for games that use 3D acceleration...that can be VERY deceiving ;-) I have a VERY shitty Pentium III computer with a very bad motherboard (only 2x AGP, not even 4x), it struggles on ZDoom/ZDaemon in software mode unless I go below 800 x 600, BUT it's able to run Doom 3 relatively smoothly, and even run GPGPU demos ;-)

[wesleyjohnson]

Software render (original doom rendering, not OpenGL) should work on almost anything, with only some very large wads slowing things.

If you used OpenGL hardware rendering, that depends upon the drivers and SDL and the rendering program getting the modes they want. If they don't it can drop down to OpenGL software emulation, which is really really slow. Just not having good OpenGL drivers for that particular video card will do that.

See the messages that the port puts out when starting, which are visible again if you scroll back up after shutting the program down.

I just had to get proprietary nVidia drivers for Linux 2.6, just to increase OpenGL rendering from 1-2 fps (due to software emulation of OpenGL) to now having 15-36 fps (hardware supported OpenGL) (no shaders present on a MX 440).