Calculating GPU hashrate (graphs/sec)

Given the specs of a GPU, what how would you calculate its graphs/sec rate?
For example, I want to calculate the theoretical hashrate of a ZOTAC GeForce GTX 1070 Ti 8GB 1607 Mhz Base/1683 MHz Boost Clock, 8008 Mhz Memory PCI-E 3.0, DVI-D, HDMI 2.0, 3x DP (ZT-P10710C-10P).

What are my equations and variables to consider.

I don’t think its feasible to calculate the theoretical graphrate. Your best guess is buying it and testing it out.