H264 vs H265
These are technologies for video encoding, as expected h265 is “better” or more recent than h264.
H265 is capable of delivering the same quality as h264 for (about) half the bitrate, at a very small latency cost.
So, as an example we have recommended 30mbps for 1080p on another article - this recommendation is for h264, if you have h265 capable hardware, 15mbps should provide the same results!
H265 support is highly recommended for 4k