Question System performance with RX 580 vs GTX 760

[biL4]

Hello!

So i have this confing:

Asus M5A99X EVO
FX 8370 4.3GHz - DeepCool Gammax 300
Ram - 8 GB 1600MHz
120Gb SSD
ASUS GeForce GTX 760 DirectCU II OC 2GB GDDR5 256-bit vs
XFX Radeon RX 580 GTS XXX Edition 4GB GDDR5 256-bit
PSU - Corsair CX750
Dell 144hz monitor

So i just bought the RX 580 and set it. Basically the reason for this upgrade was to have better FPS and overall performance in Fornite.
The improvement is very easy to spot but when playing in a part of the map that has more objects to render and while in aggressive combat with multiple players I experience some serious frame drops that are not present in the same manner on the Gtx 760. After a couple of hours I decided to switch back the cards.

Any thoughts on this?
Thnx

 

[Dark Lord of Tech]

You need to get off the FX platform , to fully utilize better performing cards.

 

[biL4]

Thnx for the answear !

But is it normal to have better performance on gtx 760 than on rx 580 ?