GL-B1300 slow speeds with 22.03 vs stock

Hey, I just flashed Openwrt 22.03.4 on my GL.iNet B1300 and I observed that over cable I get around 150 mbps download speed using speedtest, my ISP provides gigabit internet. On the stock firmware of the router that is also based on Openwrt I can get up too 800-900mbps and if I remember correctly I was able to achieve similar speed with 19.07. I did a bit of research and people online recommend turning on software and hardware flow offloading and with this I get around 200 mbps but nowhere close what I was able to achieve in the past. Besides the offloading setting and the interface/wireless settings necessary to connect to the internet everything I kept default. Can you guys help me with any other advice?

You may check the CPU idle - if going close to 0%, you are likely running it on single CPU core. Your device is stated to be quad-core. You can also monitor it via "htop".

Hey, thanks for the advice. I started a download on my laptop and then went into htop. One core seems to be hit the most with 70% utilization with the rest around or less than 10% but overall only 2 processes (htop and /usr/sbin/hostapd -s -g /var/run/hostapd/global) use any cpu above 0.0% . I tried installing/enabling irqbalance but this did not improve performance.

You may try with iperf or some other means to generate traffic between the WiFi and the wired LAN to see if it's a WAN issue with the NAT performance or with the WiFi itself.