Little upgrade GTX 645 to GTX 1080 : r/pcmasterrace
nVidia GeForce GTX 645 1GB GDDR5 HDMI DP DVI Graphics Card 0X1F5R (Lot of 2) | eBay
NVIDIA Geforce GTX 645 – Second Circuit
GTX 550 Ti benchmark with Athlon II X4 645 1080p, 1440p, Ultrawide, 4K benchmarks at Ultra Quality - GPUCheck United States / USA
Epic IT Service - Geforce GT 640 for Mac Version, with 1GB GDDR5, PCI Express Gen 3.0, DVI-I DL, HDMI 2.0, DisplayPort 1.2, DirectX 12 (Boot Camp) Light Performance Board - OEM : Video Games - Amazon.com