The Nvidia RTX 2080 Ti costs $999 and if you thought that is expensive then think again because the NVLink that you will need in order to get 2 of these cards to work together does not come cheap either. An NVLink will cost you $79. That is a lot of money for a bridge.
This means that if you are looking to pair two of these cards in SLI then you will be paying at least $1998 for the cards and the additional $79, which adds up to $2077. While a single card is the better bet for gaming, you might need another one if you are looking to use some other applications as well.
It will be interesting to see how people use these Nvidia RTX 2080 Ti graphics cards and whether people are going to use them in pairs. I am sure there will be enthusiasts out there that will do it for the benchmarks as well as the bragging rights so stay tuned for information regarding what 2 Nvidia RTX 2080 Ti graphics cards can do and how well they scale.
As of right now, there are two generations of NVLink that you can choose from. The first generation is capable of 100GB/s. NVLink 2.0 can reach more than 300GB/s. This is faster than the PCIe bus interface in terms of bandwidth. It is interesting to note that while the Nvidia RTX 2080 Ti and the Nvidia RTX 2080 can be paired in SLI, such is not possible for the RTX 2070. It is possible that 2 RTX 2070 graphics cards would be able to compete with the Nvidia RTX 2080 Ti provided that there is proper SLI support.
The RTX 2070 does not have NVLink connectors and I am sure that Nvidia did not want to cannibalize its own graphics cards. This is not something new as the GTX 1060 also does not have SLI connectors. This precaution has been taken so that people do not get 2 of these graphics cards in order to get performance similar to the GTX 1080.
We have not got the official word from Nvidia about the matter but it will be interesting to see what the company has to say in this regard.