I'm trying to run this game on a modern laptop. It's got no graphics card, but otherwise exceeds every spec in the minimum requirements by a couple orders of magnitude, and I've turned off the hi-rez 3D option so the lack of a graphics card shouldn't be a problem. But I'm getting about 1-2 frames/second!
What do I do?

Make sure that the star blurring is turned off in the game options. Should hopefully fix your problem.

Did. I turned /every setting/ to minimum. Same thing.

If it's what I think it is (an Intel IGP) they can't compute 3D for ****. Whats the full system specification?

Windows Vista Home Premium, Service Pack 2, 32-bit
Intel Premium Dual CPU T3400 @ 2.16GHz
2.00 GB RAM

Thing is, I've run things that ought to be /far/ more 3D-costly, such as HL2, without any trouble. I expect this sort of dragging with, say, Batman: Arkham Asylum, but not with a 13-year old game.

Could be a problem with the glide emulation then. I'm not sure as I've never tried running it on integrated graphics.

Is there some way to test this?

This is quite annoying. One of the main reasons I buy old games is so that I can get away without a graphics card - generally, even if they call for one, it's so old and weak compared to modern hardware that my CPU can take up the load without difficulty. Having this sort of crap running a game in a mode that's supposed to work without a graphics card at all is frustrating.

That's because the stock game runs in software mode without a Voodoo 1 or 2 graphics card present. This GOG release doesn't default to that, but it comes without the other problems that were present with I-War in XP or later operating systems.

Wait for Ravenger to show up, he's one of the former developers who'll be able to shed more light on this than I can.

Oh, hey! Killing the sound fixes it! The only problem is, if I launch iwar.exe directly, the graphic get badly glitchy - all the text becomes unreadable hash, and moving objects sometimes leave 'trails' from their edges. I can't take a screenshot; it just some out all black. It's been doing this from the start; the only solution I've found has been to always launch the game through the iwar_start.exe.
Do you know what other options the launch wrapper passes by default?

Also, now that we've identified the problem, is there any hope of /fixing/ it? I'd like to be able to hear my laser guns going 'PEW PEW PEW'. Not to mention that audio cues would be a big help in something as information-dense as a 3D combat simulator.

If you were running XP I'd say disable hardware sound acceleration, but Vista doesn't support that.

Are you running the game in XP compatibility mode? Or even Windows 98 compatibility mode?

No, the only compatibility option I'm using is Run as Administrator. I /tried/ both XP and 98 modes, but they made things worse.

Thinking about this I don't think you're running the game in glide mode in that last test so it may not be sound related.

Make sure your shortcut has -b -16 and -xsound in the command line. That'll run the game in glide mode and disable the sound. I've got a feeling that the game will still be slow.