This 8 pin CPU connection on the motherboard also allows the use of a 4 pin fitting from earlier power supplies. You can also purchase an adapter to use all 8 pins which is recommended. Many of the newer boards use 8 pins to help stabilize the power to the processor as there has been a shift from 4+1 phase power boards to 8+2 power phase boards. Each phase takes a turn in delivering power to the system and this can help when stressing the board and chip.
If you've decided to buy a power supply in lieu of a cable then select a power supply and click on specifications afterwards. You will typically see a listing of the connectors available on the power supply you have selected. Sometimes it will say EPS 8 pin or 4+4 pin or similar.
You do not need the adapter. The motherboard you chose only needs the 4 pin CPU power connector.
And you wouldn't need the adapter anyway. Using the 4 -> 8 pin adapter will not increase the amount of power you can pull from the CPU power plug.
That motherboard doesn't have the 8 pin connector , but my first choice was a Gigabyte board that did.
My current PSU is barely enough for what I have right now according to newegg's wattage calculator.
It calculated 479W and my Fortron is only 500W.
If I buy a bigger PSU I would like to buy the one with the proper connectors, otherwise the adapter should be fine.
My question is:
If I buy a Gigabyte board like this, which kind of PSU will have the proper connectors?
Any good, modern PSU will have either 4 and 8 pin or a single 4+4 pin connector.
If you are not going to upgrade anything but the motherboard, your present PSU will work. Depending on how the motherboard is oriented, plug the 4 pin connector into either the lower or right half with the yellow wires facing outward toward the edge of the board.
Using the adapter does not accomplish anything. You are still going to be limited by how much power the PSU can provide. It's like plugging a power strip into the wall. It doesn't matter how many outlets on the strip. You are limited to what the wall socket can provide.