Hello,
With Intel chips, speed is not so important, so anything that is cheap and appealing is recommended. I have installed the following in two different setups and am very satisfied.
G.Skill Trident Z RGB (2x, 8GB, DDR4-3000, DIMM 288)
Corsair Vengeance LED (4x, 8GB, DDR4-3000, DIMM 288)
As a tip: It's better to use two 8GB bars than one 16GB bar.
According to ASUS, this motherboard is compatible with an it-9700K.
see: https://www.asus.com/us/Motherboards/ROG-STRIX-Z370-I-GAMING/HelpDesk_CPU/
However, I do not know which BIOS version is on the mainboard when it is delivered.
No. Only with the 8th generation. Via Bios update also with 9th generation. See manufacturer's website: https://www.asus.com/ch-de/Motherboards/ROG-STRIX-Z370-I-GAMING/HelpDesk_CPU/
For the i7-7700K I recommend a motherboard with a Z170 or Z270 chipset.
Hello Pfnusli
I have not installed 32 GB RAM on my mainboard, but you can simply install 2x16 GB RAM bars. But make sure that they are DDR4 RAM, otherwise you won't be able to use them.
Here is an example:
Corsair Vengeance LPX (2x, 16GB, DDR4-2666, DIMM 288)
Greetings