Netgear WNR3500L v1: slow network performance


I have Netgear WNR3500L v1 and would like to achive as good performance on LEDE as on original firmware.
When using standard firmware from Netgear I can achieve 250Mbps from WAN, but when using LEDE 100-120Mbps is maximum.
I would like to be able to achive 250Mbps as on standard firmware. I tried to find something regarding ctf.ko, bcm_nat for LEDE or OpenWRT but without any luck.
Could you advise me how can I increase performance of my router? As it has 4x 1Gbps LAN and 1x 1Gbps WAN I would like to make use of them.

Thank you!

That speed reduction is expected because the CPU is not able to handle the speed. The stock firmware implement some sort of hardware nat that LEDE doesn't do, so the CPU has to work harder resulting in lower total speed.

Have a look at Qualcomm Fast Path For LEDE, a recent development that could help you.