Good afternoon. So I have a PNY VCGGTX550TXPB GTX 550 Ti graphics card and I want to SLI it with another one. Now the problem is that its been discontinued and the current one is the PNY VCGGTX550TVXPB GeForce GTX 550 Ti graphics card. I'm wondering if I can SLI one of each or do I need to get hunt down and order a second identical card as the one I have? Thank you for your time.