Renderer change and FPS increase when streaming with OBS

[Horolynn]

Sounds bizarre, at least to me it does but hear me out.
Whenever I hit "start streaming" or "preview stream" in OBS, PPSSPP's renderer changes to D3D10, as shown by rivatuner osd, and the framerate goes up even above 60 fps even though I have the option to limit the framerate to 60 checked and some games have their own locks even lower. It's not just an error in display either, as I can clearly feel the difference and it's much smoother/the input lag is not there anymore. I've played around with a few options but I can't reproduce it unless I use OBS. Can someone explain it to me, and possibly tell me how to make it happen without OBS?