Today I did a lot of testruns to see what the most optimized settings where for 21:9 aspect ratio recordings. It's not razor sharp but will do.
For a Full HD example see my other 1920x1080 video (Dutch): https://youtu.be/bHgrYCPFyt8

OBS (Open Broadcaster Software) Software: https://obsproject.com
rFactor 2: http://www.rfactor.net

MY HARDWARE:
Windows 10 Pro 64-bit
Intel Core i5 4570 @ 3.20GHz
16,0GB Dual-Channel DDR3 @ 799MHz (9-9-9-24)
MSI B85-G41 PC Mate(MS-7850)
LG ULTRAWIDE (3440x1440@60Hz)
2048MB ATI AMD Radeon R9 200 Series (MSI)
SSD Harddrives

OBS SETTINGS:

Scene Source: Game Capture
Settings (standard + some changes):

OUTPUT
Output Encoder preset: faster
Recording quality: Indistinguishable Quality

VIDEO
Base canvas: 3440x1440
Output resolution: 1720x720

VIDEO EDITOR:
Hitfilm Express (Awesome): https://hitfilm.com

Comments

Your comments are very welcome, please be nice ;)