At the ceremonial pre-launch press briefing (EMEA), we specifically asked NVIDIA if 4-way SLI was a feature supported with GeForce GTX 670. At the time, it seemed like a silly question to ask, since GTX 670 has the same GPU as GTX 680, which supports 4-way SLI, and its reference board is pictured with two SLI bridge connectors. NVIDIA representative's response was in the affirmative (that it does support 4-way SLI). However, post launch, some sites that had four GTX 670 samples to play with, tried getting 4-way SLI numbers for science, to their failure.

Apparently NVIDIA wrote to some tech publications, such as PC Perspective at the last moment before GeForce GTX 670 launch (we didn't receive such a communication), telling them that the GPU does not support 4-way SLI. The email read "As I'm sure you can imagine, we have to QA every feature that we claim support for and this takes a tremendous amount of time/resources. For the GTX 680 and GTX 690, we do support Quad SLI and take the time to QA it, as it makes sense for the extreme OC'ers and ultra-enthusiasts who are shooting to break world records."PC Perspective wrote back questioning the move to deprive 4-way SLI. "But with the similarities between the GTX 680 and the GTX 670, is there really any QA addition required to enable quad for 670? Seems like a cop-out to me man..." NVIDIA later replied saying that 4-way SLI could be added to GTX 670 in a future driver update. "Change in plans.....we will be offering 4-Way SLI support for GTX 670 in a future driver." NVIDIA realised that it's not the best thing to do, to deprive 4-way SLI support to the GTX 670. Granted, a very tiny minority of enthusiasts use 4-way multi-GPU, but that's no excuse. Seeing as how the GTX 670 2-way SLI is just 2% slower but 20% cheaper than GeForce GTX 690 while being even more energy efficient, we kind of see a commercial motive behind NVIDIA's move. Yet it's welcome news that NVIDIA will correct this with a "future driver update". Let's hope the issue stays hot, till the said driver update is a reality.