My MP4 Recordings Are FAR More Laggy As Opposed To My AVI

[SirSnugsGaming]

So i recently started getting back into recording gaming videos and what i found out was honestly shocking. When i try to record with AVI i get no fps drops in game (if so very little) and the recording comes out beautifully! Great product right?! But when i try to record with MP4 (including hardware acceleration) the frame rates in game are just horrible and the recordings are barely 60 fps. Now at first i believed this bug was specific to one game but it isnt! Any game i try to record in mp4 is always laggy, but it isnt in AVI? Ive checked all my settings and there doesnt seem to be anything out of the ordinary... Please someone help!

OS: Windows 10
Video Card: NVIDIA GeForce GTX750 1GB
Memory: 12GB
Monitor Resolution: 1920x1080
Video Editor: Does not apply because im referring to raw footage
Game Problem: Everything
Video Type: MP4

[Piotr]

Hello.
Recording in AVI has better performance than recording in mp4. How many fps you get when recording in mp4?