Pbatt, Unfortunately the R630 doesn't look to support the use of internal GPUs. The slot specifications you listed are correct, but it is likely due to a lack of a power connection for the GPU to use, that makes it unsupported. Hope this helps.
Apparently trivial question... but I'm failing to find an even vague answer.  We have an R630 and we are considering adding a video card to run computations on GPU. The manual states that slot 2 is a "PCIe x16 connector with x16 bandwidth; 3/4 length , full-height". So a half-height graphic card should fit there without problem. But then the manual makes no reference whatsoever to graphic cards, and www.dell.com/.../poweredge-gpu doesn't mention the R630 at all. Are we missing anything?
GPU on Poweredge R630