EVGA GeForce GTX 550 Ti 2048 MB GDDR5 PCI Express 2.0 2DVI/Mini-HDMI SLI Ready Graphics Card, 02G-P3-1559-KR NVIDIA 2-way SLI ready 4356 MHz Effective memory clock and 1903 MHz shader clock PCI-Express 2.0 GeForce GTX 550 Ti with 951 MHz core clock 2048 MB 192-bit 0.5ns GDDR5 memory GeForce GTX 550 Ti with 951 MHz core clock PCI-Express 2.0 2048 MB 192-bit 0.5ns GDDR5 memory 4356 MHz Effective memory clock and 1903 MHz shader clock NVIDIA 2-way SLI ready