Is one not enough? I've had no problems running this game on a single 1080 Ti at 1080p resolution. Are you your graphics drivers up to date, GPU temperatures under control, and CPU not bottle-necking anything? What resolution are you hoping to play at?

jschu995
If you are not getting a satisfying perf it might be your CPU

I am running a 5600X CPU + 1080ti and getting around 120fps on average on 1440P in warzone. I contemplated picking up a second 1080ti to run in SLI but the performance gains would be so minimal it is just not worth the cost of another card especially with the current market pricing. So yes, hold out for a larger upgrade. Not to mention when the market dies down for GPUs, you will have (2) older gen graphics cards to sell for a fraction of the price you paid for them now.

My understanding is that SLI is being deprecated.  One 1080ti should be fine until you can afford a better card.  Hopefully you'll see a wave of 2000-series or 3000-series hitting the used market in July due to Ethereum miners leaving the market.  They'll have been used for mining, but they'll also hopefully be at a more attractive price.
 
Don