FRAMERATE
HOW FRAMERATE AFFECTS YOUR PLAY
Framerate refers to the number of Frames Per Second (FPS) your computer can display.
The maximum framerate Doom or Doom2 will display is 35 FPS. Because of the impact it has
on your play, the importance of achieving the maximum frame rate cannot be over-stressed.
Picture a cartoon, made of 35 images that change slightly between each different scene, so
that flipping through them causes a character to animate and move across the screen. Now
remove some pages and flip through them again. Every time you get to where one of the
pages (or frames) is missing, your animated character will seem to "jump" from
one place to the other. This happens when you lose frames in a deathmatch; every frame
that you drop causes your opponent to skip across the screen, spoiling your aim,
situational awareness, etc. Using an under-powered computer harms your framerate, and in a
deathmatch a player will be at a disadvantage if his framerate is considerably slower than
his opponent's.
DETERMINING YOUR FRAMERATE
First set your system up to run the game as you normally do, with proper screen size,
and sound and mouse drivers, loaded. Then type the following command line in your Doom2
directory:
doom2 -timedemo demo2
(Use demo2 because it remains unchanged across all versions of
Doom2, so you can compare results more readily.)
As it loads, the game will complain that it cannot find the file
demo2, but you can ignore that message, it's a bug. Doom2 will launch and display demo2,
probably faster or slower than normal speed, depending on your hardware. When the demo
completes, the game will exit and display a line that says:
xxxx gametics in xxxx realtics
You derive your framerate from this by multiplying your gametics
by 35 and dividing by the number of realtics. Because the maximum frames per second (FPS)
that the Doom engine can display is 35, if the number you get is over 35, then you are not
losing frames in the single-player game. Playing a multi-player game over a network seems
to provide the same framerate as the single-player game. There is greater overhead in a
modem game, so your single-player framerate should exceed 40 FPS in order to be confident
that you are not losing frames.
To compare your framerate to others', check the Doom Benchmark
Results page at:
http://www.complang.tuwien.ac.at/misc/doombench.html
This page will allow you to see what framerates other systems are
able to achieve running the shareware (because it's freely distributed) Doom under
comparable conditions. By the way, framerates are a bit higher in Doom than Doom2, though I
can't really figure out why (the added textures?).
IMPROVING YOUR FRAMERATE THROUGH HARDWARE
The two most important factors influencing your framerate are processing power and
video performance, so the most important items to upgrade are your processor and your
video card. Generally, the minimum setup that can achieve 40 FPS in full-screen mode is a
90 MHz Pentium with local bus video. Do not underestimate the impact your video card's
performance has on your framerate. When the PCI video card in my old 90 MHz Pentium
failed, I used an older ISA card until I could get a replacement, and I suddenly went from
40 FPS to less than 15! If you have local bus video, upgrading your CPU will do the most
to improve your framerate. When looking for a good video card, check benchmarks for DOS
performance, as sometimes a less expensive card is a better DOS (as opposed to Windows)
performer.
Doom will run on four megabytes of RAM, but prefers eight or
more. The detriment to running Doom with too little RAM seems to be the occasional hitch
here and there as the program accesses the hard drive, rather than the general choppiness
of a reduced frame rate. The hitches can be fatal, nonetheless, so shoot for at least
eight megs.
IMPROVING YOUR FRAMERATE BY TWEAKING
- First, if you are using Windows '95, you should run Doom in pure
DOS mode. Access the "properties" dialog box, and make sure to check the
"force MS-DOS mode" box. This will make a big difference in your
framerate.
- Doom will run slightly faster with the "-nomusic" option
(-nosound will boost your performance even more, but that's a trade-off you probably do
not want to make).
- Boot clean. Doom does not need memory managers, disk caches or
anything of that sort, and will run faster without them. Booting from a clean floppy disk,
or booting while holding the <F5> key will bypass your startup files. There are also
ways to set up multiple configurations under DOS that will allow you select a clean
configuration from a boot menu. Just be sure to load your mouse driver after a clean boot.
- Reduce the screen size. By
reducing the screen size a couple of notches you can boost your frame rate significantly.
You'll need to experiment to determine the extent of the trade-off in deciding how much
viewing area you are willing to sacrifice for a smoother game.
- Play in low detail mode. You can toggle between normal and low
detail mode by hitting the <F5> key. Personally I find it impossibly blurry, but I
have never had to struggle too badly with an under-powered PC. There are many players who
swear that they can play just fine in low detail.
- Experiment with your CMOS settings. WARNING! Before messing
with any settings in your CMOS, be aware that you can screw your system up by messing with
these settings incorrectly. If you do not feel comfortable with that, then you should
probably just live with your framerate. If you do mess with those settings, and do mess up
your machine, you should feel really stupid, having just read that last sentence. What I'm
trying to say here is, don't blame me if you end up screwed. That having been said, here
are some other things to do in order to boost your framerate. The best way to test these
kinds of tweaks is by changing one setting at a time, bench-marking the system in between
each change.
Turn off video shadowing in CMOS setup. Doom will often run better with this option
disabled. If you have a 486, play with your memory wait states, quite often machines ship
with the most conservative settings on the wait states, and you can increase performance
by changing them. Generally, lower wait states are faster, but setting them too low for
your machine will harm its performance, so experiment. Test the difference between
write-back and write-through modes for your cache, if those options are available.
ACKNOWLEDGMENTS:
First and foremost, thanks go to MrsBlue for being an amazing editor, as well as for
her patience.
Again, a huge thank you to Abraxas for contributing significantly to this
document (and for being my favorite deathmatch opponent).
Thanks also to the many contributors to rec.games.computer.doom.playing, too
numerous to mention.
Finally, thanks to everyone who has ever kicked my
ass. See guys, I was paying attention!
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