I have an older Mac Pro that has a 8400GS video card in it. Are there any newer drivers than those that came with thecard, which was bought this past June, 2016?

If you have an 8400GS that is specific to the Mac then the last known drivers have to be provided by Apple. Most likely in the operating system. Due to the age of the card I don't really expect anything newer than what you've already got.

Thank you. A simple, direct, intelligent response, something that is getting rarer and rare on message boards. Your momma raised you right.
Any way, I card itself is about 4 months old an since my first homebuilt (around 1992) I been under the impression that unlike ATI, nVidia's drivers never go out of style.
The main reason I was asking is the display is locked at 1280x1060(?) and cannot be adjusted. I guess I'll just have to save more pop bottles for the 3¢ a bottle refund so I can get a newer card.  Has to be a PCI-e one though.