F1 2015 Steering input, graphic lag, etc

[Joe Ethier]

PC spec:
GPU: Amd Sapphire Radeon 6950 HD 2gb
CPU: Amd FX-8350 8 core
Ram: 16gb
Monitor: LG full hd 1920x1080 60hz

Hi there,
so I've got F1 2015 on my pc and cannot play because it's too laggy.
Problems:
-I've got a SRW-S1 mounted on a G27 by quick release. The thing is that in the game config, for turning left example I chose Axis - but the game recognize only 1 full steering wheel so when I play, the steering wheel is laggy because I've got two steering wheel turning Axis - at the same time. In rFactor 2 for example or other games, it recognizes 2 different joystick so no problem.

-I cannot play because the FPS are waayyyy too low. But what's strange is that the difference between extra graphic and extra-low graphic is only 10 FPS...On F1 2014 or other games I can easily play full graphic and it doesn't lag. Is it a setting somewhere that I'm not using well?

-My G27 pedals do have a 40%-50% deathzone automatically. I can't change anything...

I hope you have the same problem and could help me, please.
Thanks!