dmesg | grep -i duplex gives no result here, although the modem LAN connection is green instead of blue, indicating a 1 Gbps connection, also one LAN cable has a 1 Gbps connection, so I'm afraid you can't tell this way if it has a Gigabit connection.
Some people say there are two sorts of Cat5e: two pairs and four pairs. The four pairs is Gigabit-capable.
With my E3000 and some Arris modem, if it gives a blue WAN light on the router, then it does not have a Gigabit connection and the solution is to remove the WAN connection cable for a while (0 to 30 seconds) and reinsert it, repeat until you get a green WAN light.
Slobodan,
I guess I could try a CAT 6 cable but I doubt that it would have any effect. I'm just guessing out of the blue here but IF a CAT 6 cable would improve the situation then it has something to do with how DD-WRT negotiates link speed. The same router running stock firmware and the same CAT 5e cable gives 240/98 Mbits.
I have been doing some tests but I forgot to document all of them. I can't remember if I used Tomato by Shibby or if it was DD-WRT. In one of the builds there was a built in command (forgot the name of it) that you could do "command show" and I could see that the WAN port was indeed negotiating 1000 Mbits FD. I think it was in Tomato. However the performance was the same as with DD-WRT so I went back to "DD-WRT v24-sp2 (03/17/13) mega (SVN revision 20979)". With some tweaks such as OC the CPU to 532 MHz I got 130/80 Mbps from the E4200. Once I activated my services that speed quickly decreased to around 115-125/70 Mbps.
Further research indicates that it's currently not possible to achieve stock speeds due to Broadcom's closed driver binary.
DD-WRT is feature rich but I don't use all of the features. I was using OpenVPN until I realized that it was consuming a lot of processing power so I have decided to exclude that from the equation and run it from a separate box.
I think I will have to look for home Gigabit routers with SNMP support because that is my #1 need. _________________
Home users are likely to notice no difference between Cat5e and Cat6 performance. For them Cat6 is a fancy, more expensive version of Cat5e. _________________ 2 times APU2 Opnsense 21.1 with Sensei
2 times RT-AC56U running DD-WRT 45493 (one as Gateway, the other as AP, both bridged with LAN cable)
3 times Asus RT-N16 shelved
E4200 V1 running freshtomato 2020.8 (bridged with LAN cable)
3 times Linksys WRT610N V2 converted to E3000 and 1 original E3000 running freshtomato 2020.8 (bridged with LAN cable)
