GTX 980Ti and My Power Supply

[PyreUK6]

I currently have the build below:

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-6400 2.7GHz Quad-Core Processor (£165.46 @ Scan.co.uk)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£29.99 @ Amazon UK)
Motherboard: MSI Z170-A PRO ATX LGA1151 Motherboard (£86.55 @ Amazon UK)
Memory: Corsair Vengeance LPX 8GB (1 x 8GB) DDR4-2666 Memory (£31.49 @ Ebuyer)
Storage: Sandisk SSD PLUS 240GB 2.5" Solid State Drive (£57.98 @ Novatech)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£41.99 @ Amazon UK)
Video Card: Asus GeForce GTX 970 4GB STRIX Video Card (£215.99 @ Amazon UK)
Case: Phanteks ECLIPSE P400 ATX Mid Tower Case (£55.89 @ CCL Computers)
Power Supply: Corsair Builder 500W 80+ Bronze Certified ATX Power Supply (£42.99 @ Amazon UK)
Total: £728.33
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-07-26 20:56 BST+0100

I would like to add a GTX 980Ti SC from EVGA with my current power supply until December. I will not be overclocking my GPU and it will be cheaper than a GTX 1070.

Will I be fine until then?

 

[hang-the-9]

Why a 980 Ti now and not a 1070? At least on Newegg the two are pretty much the same price, and the 1070 is a better pick. As fast as the 980 Ti or faster, 100 watts less power use.

 

[PyreUK6]

Why a 980 Ti now and not a 1070? At least on Newegg the two are pretty much the same price, and the 1070 is a better pick. As fast as the 980 Ti or faster, 100 watts less power use.

In the UK, the GTX 980ti is £50 cheaper but I have decided after posting to get the GTX 1070