I'm connected by 500 Mbit Vodafone cable to the internet. I'm just a private novice user.
Since the former Sagemcom FAST5460 router didn't fit my needs any more, I used an Archer C2 v3 modem together with the cable router in bridge mode. Someday the Archer wasn't able to connect any more and I changed TP-Link firmware to openwrt. Everything was fine for a pretty long time.
A couple of weeks ago my internet only connected at about 200 Mbits by LAN. Vodafone told me, that I need the Technicolor CGA4233DE router. Together with this router and the Archer I still get only about 200 Mbits by LAN. The Technicolor for itself runs at 500 Mbits by LAN.
i think your Archer C2 is too weak to handle the 500Mbps.
install htop :
opkg update
opkg install htop
and then run it. htop
once it is runing, start a speedtest, and see the cpu load in the graph at the top. if it is close to 100% then you're good for buying a more powerfull router.
Any MT7621 cpu based router can handle 1Gbps fiber without problem (as long as you enable HW Nat in the firewall settings)
Thank you very much for your answer. I will test the Archer. Due to Vodafone setup regulations I have to wait now for 7 days before I can activate bridge mode again
In normal use, here with spotify streaming and running a video on youtube the load is usually below 10%. Only when I start an instance it comes close to 100% for a few seconds.
I have no idea what this option does, but it makes a great difference. The cpu load doesn't reach up to 100% an max download speed was in several tests between 370 and 399 Mbits.
Basicaly it offloads the CPU from some tasks, so it goes faster.
The oem firmware usualy use proprietary drivers, not open source and that openwrt can't use, they are more efficient and give better results. and it probably use Hardware offloading, which is even more efficient than software offloading.
If you go back to the stock firmware, you'll probably see even more speed improvement.
From my point of view, the best devices for openwrt are MT7621/MT7622 CPU based devices, because hardware NAT is supported, and they are cheap. Then the X86 devices, because they are generally powerful enough not to need hardware acceleration.
On my MT7622 cpu based router, on a 1Gbps fiber line, without any offloading my cpu load is 75%, with hardware offloading enabled it's less than 3%