Aw5585,   The reason you're seeing the training error is that while the R730xd supports the Quadro K1200, the R730 doesn't. The R730 does look to support the Quadro P5000 (p/n# 00MKC) and M5000 (p/n# Y1P3V) models though.   Let me know if this helps.
From Dell-DylanJ's response in this link: [URL] ...it appears that the R730 (well R730XD) should be OK with a Quadro K1200.  However, I have tried installing one in the X16 slot (slot 4) in a Dell R730 and consistently get a PCIe link training failure error for that slot on boot. Both BIOS and iDRAC are on the latest versions. I'm slightly at a loss as to how to update the PCIe device firmware (suggested further down the error message) if I can't get the server to recognise the card in the first place. The card doesn't have any additional power ports and recommends a 200W power supply (the server has 750W supplies), so I am assuming (perhaps wrongly) that the GPU upgrade kit is not required. Any suggestions as to what I am doing wrong much appreciated. (The card is intended for use in a ESXi v6.5 VMWARE client on the machine.) Many thanks.      
Quadro K1200 in Dell R730