I-War was designed to run on 3Dfx cards back in the day, which gave us an astonishing resolution of 800x600. Without one of these cards it will only run in 640x480, without 3D acceleration.

But fear not! You can change this nowadays. There are various programs out there that can emulate a 3Dfx card and even bring your resolution up to 1920x1200! Just to name a few:

• NGlide
• dgVoodoo
• zeckensack

Usually, you just copy one of these wrappers into the game directory, configure the resolution and you are set.

NOTE: The GOG version of I-War already includes a 3Dfx wrapper.

The DEP of new Windows versions prevents the game from loading. Follow these steps to disable the DEP:

• Open Control Panel, select "System Security" then "System" followed by "Advanced System Settings". Choose the Advanced tab, then "Settings..." in the Performance section.
• Choose the "Data Execution Prevention" tab and add iwar_start.exe to the exception list

The game seems to slow down extensively in some setups, when the option "Blurred stars" is set active in the settings. Just disable it.

A. Run the dxdiag.exe from "program files\DirectX\". Disable the "Direct Draw Accelerator" under the Display tab. That's it!

If you stick the dxdiag.exe on your desktop as a shortcut you can swap in and out of Direct Draw easily. Also you will not have to re-boot your system.

Solution #1: Set the compatibility mode of the game to Windows 95.

Solution #2: The problem seems to be gone in Defiance. You can run the original missions within the Defiance game engine (although this isn't supported, it should generally work).

Instructions (copied from the now defunct Atari Community):

"This is still slightly crude, but the game is running, and will hopefully be fully playable. Here's what I did:

(a) Copy IWDE.exe, DeIsL1.isu, and Dreadnaught.ini from Defiance to I-War.
(All other files here and inside "brender" are identical from I-War to Defiance, aside from the loading screen which we want to keep :) Remember to update your shortcuts to the game to point to IWDE.exe (or else rename IWDE.exe to IWar.exe).

(b) The psg/resource directory...
This contains the actual game data, so we certainly want to keep most of the original files, however the new executable will also require certain resources from Defiance that do not exist in I-War (this applies to both the slabbed and unslabbed files), so we need to copy these files over. The easiest way to do this is as follows:

1) Deslab all *.slb files for both games, and add "-noslab" to your game shortcuts.
2) Under I-War\psg\resource make a new directory (say "x")
3) Move all the following directories into "x": art, sh_3dh, sh_3dx, scripts, shapes, sounds.
4) Copy the Defiance versions of those same directories into the I-War resource directory.
5) Delete the new copy of the scripts\missions directory.
6) Copy or move the directories under "x" back into the resource directory, overwriting everything when asked.

Lastly, we need to add back the Defiance init and gui scripts. These are the only resource files existing in both games where I have used the Defiance versions, as the game will not run without them:

7) Copy the "init" and "gui" directories from Defiance\psg\resource\scripts into I-War\psg\resource\scripts (overwriting).

8) Also copy "excelrichsys.csv" from Defiance\psg\resource\geog into I-War\psg\resource\geog (overwriting). (This merely fixes a typo.)

This will give you a resource directory that contains all the original I-War files, plus all of the new files from Defiance (except for the definitely-unwanted Defiance mission and briefing documents).

This isn't necessarily the best possible arrangement, but it is simple to do. Some of the new files will be superfluous to the original game regardless of the updated game engine, but any such files will certainly not cause problems, and I believe that steps (7) and (8) cover the only files which ought to be updated to the Defiance versions from their I-War originals (See next reply below for details on this).

You'll find that the game has acquired some of the Defiance characteristics (the all-red mission selection screens; the ability to zoom; the inability to enter and navigate the 'virtual bridge') but with a bit of luck, the game will actually be fully playable. I wouldn't be surprised if there are problems, mind -- this is something of a "cross your fingers and hope for the best" sort of operation after all -- but at this stage I'd also not be surprised if it all works properly :)"

The 3Dfx-Version of I-War often will not register weapon hits, because on modern computers the game might run too fast, even with a fixed framerate of 60 FPS (which most monitors run at).

The Solution:

If you have an NVidia graphics card, go to the NVidia system settings (right-click on the desktop) and then to 3D-Settings.

Now change your vertical synchronisation (v-sync) to adaptive (half frequency).

The game will now run with 30 fps and your hits should be recognized.

Remember to revert this setting after you've finished playing, since the setting limits anything shown on the monitor to 30 fps.

If you have an AMD graphics card the tool Radeon Pro can help you setting up a fixed framerate.

Thanks to ChristianGS for finding this solution.