Formatting error on a HGST 4TB hard drive

[MacuserNo.42]

I have just purchased 2 HGST 4 TB hard drives to increase my storage options. I have a 2010 5,1 Mac Pro running 10.10.5 Yosemite.
I tried initialising mac OS Extended(journaled) on the first drive in bay 1 using disc utility. After one failed attempt it formatted after a second time and I thought all was fine. However the drive is only formatted to 400.09 gb and despite trying to re initialise it is stuck on that figure.
The second drive was initialised successfully in an external drive reader, and using drive genius this time, GUID partition table checked. When mounted back in the Mac Pro it reads as a 4TB drive.
Using the external drive reader and drive genius and disc utility I cannot re initialise the 1st drive to any thing other than the 400.09gb.
Any ideas on what I can do to re-format this drive correctly to 4TB , assuming there is nothing wrong with the hardware?

 

[ZVH]

Try resetting the NVRAM with the disk installed, then try re-formatting:

https://support.apple.com/en-in/HT204063

Sometimes when a new drive is installed the system won't fully recognize it. That may or may not work but it's easy to do and can't hurt the system.

 

[MacuserNo.42]

You hit the nail on the head. Thank you! Reset Nvram and the drive is now properly seen as a 4TB drive. I however had to go back to the external drive reader/enclosure to re-format/initialise, as disc utility and drive genius report back errors when trying to initialise from inside the mac. Maybe on this Particular hard drive only? I have read other posts alluding to needing to format via an external enclosure for large capacity drives on the mac pro classic.