We play on normal speed.
The game ran error free for awhile. I didn't think to check the turn count, but probably between 200-300 turns. Once we got one OOS error, it repeated several times after reloading. We rebooted, cleared cache, everyting short of actually reinstalling the game.
We gave up on that game and started a new one. No OOS problems at first, but eventually they came. We were about done with our shift, so we decided to call it a night.
I will try to record what turn the OOS errors occur on when we play again and see if there is a pattern. I will also try to get a save game file off my laptop when I get a chance.