Crossfire Rx 480 low bottom fps

Hello Community!

I have a Pc with an crossfire rx 480 configuration and encountered a problem!


CPU: i5 6600k

RAM: 1x Corsair 8gb vengeance 2400MHz

MB: MSI z170A pro gaming

GPU: 2x MSI 8gb Rx 480

Monitor: Acer 2650x1080 144 Hz freesync monitor

I set up my crossfire configuration and it worked fine in synthetic benchmarks (both cards ran with the same speed and on 100%).

But if I start Dirt rally and start the benchmark there a weird thing happens ( 4xMSAA everything on Ultra) : Pc in single card mode -->(FPS:/av./min./max) (83/69/102) Pc in crossfire mode -->(FPS:/av./min./max) (97/57/130) I get less fps on the lower end with two cards than with one

Has anybody got any idea what  causes this ? Thanks in advance !