EVGA GeForce GTX 590 Classified Limited Edition 3 GB GDDR5 PCI-Express 2.0 Graphics Card 03G-P3-1598-AR - Limited QUAD SLI Ready 3456 MHz memory clock (vs 3414 MHz reference) and 1260 MHz shader clock (vs 1215 MHz reference) PCI Express 2.0 GeForce GTX 590 Classified with 630 MHz Core Clock (vs 607 MHz reference) 3 GB 768-bit GDDR5 memory GeForce GTX 590 Classified with 630 MHz Core Clock (vs 607 MHz reference) PCI Express 2.0 3 GB 768-bit GDDR5 memory 3456 MHz memory clock (vs 3414 MHz reference) and 1260 MHz shader clock (vs 1215 MHz reference) QUAD SLI Ready