Hi, I've set up a null modem connection between two PCs - A Toshiba Satellite 430CDS (Pentium 100MHz with Win95) and a Pentium 3 1GHz with Windows 98 - and I'm able to set up a multiplayer game as usual, it connects and has zero issues running, but then after a couple of minutes or so, the game suddenly slows to a crawl and then freezes - on both machines, simultaneously. It's clearly not crashing, because the music keeps playing, and you can still even access the menu on both, but the gameplay is totally frozen. This happens regardless of if I use Windows or DOS on either machine, in any combination, and it also happens whether I use Doom95 or the original DOS executable (version 1.9).

Even more bizarre: Quake works perfectly. I haven't tested other games yet, but at the moment I think it could be a Doom-specific issue. However, I have tried connecting the Pentium 3 to a Pentium 4, and the game never froze. The Satellite does have issues with running certain DOS games (Wolfenstein 3D will not work at all) and I haven't reinstalled the OS yet - the previous owner left it in very clean condition, there was basically nothing on it except the drivers and the default Windows stuff, but they didn't have the installation media, so I suspect they might have bodged it together slightly.

If anyone knows how I might resolve this issue, advice would be appreciated. I'm going to test some other games that support null modem multiplayer, and I'll follow-up with the results.