Oh I don't game, just mentioned physX as an example. I'm planning to use them together for rendering and hopefully increased viewport performance. Seems like only the 560Ti registers in the system.
When testing rendering in 3ds max it gives me only 1 GPU core, meaning it sees only one card. It does not turn up in device manager. The 9800 even spins its fan down a few minutes after booting, so that it barely turns at all. Seems inactive.
Motherboard: Asus P6X58D-E
CPU: i7 950 running at 3.8GHz
Ram: 12GB Kingston 1600MHz (6x2GB)
The graphics cards: MSI GTX 560 Ti Twin Frozr II OC 1GB, and Asus 9800GT 512MB.
PSU: Chieftec 750W super series
Each graphics card should be hooked up right, 2x6pin for the 560Ti, and 1x6pin for the 9800GT. Should be ok, it's puzzling.