I also use the same Hauppauge HVR-2250 card, three of them, they have worked wonderfully for years now. I also have a USB tuner; the Hauppauge WinTV-HVR-950Q. That thing is more demanding on the CPU cycles but it works just as well for Over The Air (OTA) tuning as the internal card. One thing the HVR-2250 can get you is TWO tuners, it has a built in dual tuner system. The USB deal is only a single tuner.
I've used PCI x1 cards on x4, x8 and x16 slots. They always worked fine. I would check the motherboard manual to insure that there's nothing specific to that board, but I think it's safe to say it 'should' work if you wanted to go that route.