Precision 7510 with Iris Pro P580 (Xeon E3-1545M) and also AMD FirePro™ W5170M

These two graphics systems have approximately the same performance (~1200 gflops)

I was told by Dell support via chat that it is not possible to get a Precision 7510 without the discrete graphics card. That seems silly since the Iris Pro P580 provides the same performance. So two questions:

1. Is it indeed the case that a Precision 7510 cannot be purchased without a discrete graphics card?

2. If I am forced to buy this FirePro, can I at least use it in conjunction with the P580 - each driving separate displays?

Thanks,

Chris