I'm thinking of upgrading my PC and getting a ryzen 7 5700X to replace my I7 4790K and getting a RTX 3060TI to replace my GTX 1080, will this be a good upgrade?
First, Your I7 4790K CPU has Intel Socket 1150, and your new cpu is ryzen 7 5700X has Socket AM4, That's means your motherboard CPU Socket will be Intel Socket 1150 You can't put CPU in incorrect socket. do you want to upgrade? then change your motherboard.
Yeah i was thinking to get an AM4 board and get DDR4 RAM, my psu should be fine but its quite old so that might be replaced as well.
If you have the money, go for the AM5 platform. This will give you an upgrade path in the future without needing to change motherboard/RAM. AM4 has some decent CPUs currently, but it's now EOL meaning its a dead-end upgrade wise.