Two GPUs are a great system if you go with 2080TI. And one 2080 TI is itself a beast. One 2080 TI beats 3 980 cards from a few years ago.
You can always add more GPU later – and by the time you want to purchase a second GPU we might have seen Nvidia release the 3080TI.
What you have to remember is that these GPUs are big and wide…and need room to breathe. When shopping for motherboards it’s easy to be confused when looking at PCI slots. You can think…oh, this has five PCI slots so I’ll have space for five GPUs. No, you won’t.
When I purchased my first PC four years ago I bought one of the biggest motherboards. It had 7 slots. But it really can only hold four GPUs because the Nvidia cards we all love are double-width.
And in truth even four cards isn’t a good idea on that 7 PCI motherboard unless I were to use liquid cooling or simpler hybrid cooling … Like this:
If you are planning longterm for 2 GPUs it is simpler. You should be fine with just simple air cooled GPU.
I still recommend a large case and motherboard. And a Power Supply of >1,000 watts. I recommend 1,200W*. Larger cases are easier to build and upgrade, give you more options and provide more air flow. And they don’t add much cost.
For CPU I recommend AMD Ryzen as you get better performance, better price and their matching mother boards are also cheaper.
*Don’t worry…your system won’t consume that much, this gives you headroom.