OzzieDave,  Would you confirm a couple things for me?  What controller is installed in the server? What is the part number on the drives themselves? Let me know and I can verify compatibility.   
Hi anyone, I have just inserted two new DELL 3TB hard drives to my T710. They blink 10 times Green and then blink Amber and only shoe in iDRAC as PDs but have NO size. Not able to add to New VD Array either. Any Help please? I am new to setting up servers too, so please 'bear with me'. Thanks in advance   I think the drives are NO good. I cannot format them even, thanks anyway
DELL Hard Drives blinking yellow constantly on T710