Slow 3G speed on custom rom topic

I'm experiencing a slow 3G speed on my custom rom - resurrection remix. Max download speed on my device is 1.3 Mbps while on another device with same network provider can get up to 3 Mbps.(I see with my eyes).

I also didn't see someone complaining this problem with RR rom at any build version.

Is there any solution?

I heard about reflashing modem, do I need to do it?


Sent from my GT-I9082