Will that work in my current setup?
i5 6600k OC to 4.5GHz
16GB gskill dual channel
currently, i only have 1 GTX 1070 aero
Probably fearing the worst here, but hoping i dont need to replace the PSU.
What motherboard do you have? The motherboard must support SLI. Most Z170 chipset boards do, a few don't. To be more concise boards listed as SLI ready have been certified by nVidia. Others with two PCI-e x16 slots which can work in x8/x8 mode should work but are not guaranteed.
As stated you will need a better PSU. One with sufficient PCI-e power connectors. As you are overclocking the CPU and quite possibly the GPUs. Get an 850w model so you have more headroom and good one such as a Corsair or EVGA 80+ Gold. Overclocking dramatically increases peak power usage. High quality PSUs are more reliable under load. Don't get some garbage brand like Aerocool or Raidmax. 750w will work but 850w gives you more room to OC or add other components. Also there is no such thing as a too powerful PSU just too weak. You just have more power available go as high as you want.
Be sure you get an SLI HB (High Bandwidth) bridge. Not the old SLI bridge. It is necessary to unleash the more performance potential. It has been shown to make a big difference. Also get the correct slot spacing. Slot spacing refers to the number of slots between the cards. So if you have PCIe x16 (GPU 1) > PCI-e x1 > PCI-e x16 (GPU 2). You would get a "1 slot spacing" bridge.
Yes, the cards support SLI.
Yes it would work if you have enough power output from your adapter. but i'm just wondering why would you get an SLI set up instead of upgrading other parts? 4k? VR?
500w might not be enough to run 2 cards. also check that your motherboard supports sli
500w PSU will not be enough. You'll need 750w I would think
Easy enough to fit a new PSU provided you follow step by step