Youtube: GamersNexus
where you can find all the benchmarks and information you need.

for a gamer pc? then definitely AMD. (9800x3d and 7800x3d are the leaders in games, both much more efficient than Intel)

It all depends on how the PC is used
For gaming it's the best, heats up less, consumes less and is faster.
but for other applications it's less powerful

No