Posted: Sun Feb 13, 2011 15:15 Post subject: Linksys E2000 Slow LAN throughput with DD-WRT
I recently purchased a Linksys E-2000 gigabit N router. Anyway, I ran a speedtest on it before installing DD-WRT and was getting 95~98 Megabit speed from the internet to the LAN (I have 100 mb cable connection), however, once I installed WRT and ran the test again this dropped down to 30.
I reinstalled the Linksys firmware and it shot back up to 95 ~ 98. Same test site, same server.
I am running 14929 firmware for the E-2000.
Any suggestions? Would like to use DD-WRT but the slow WAN/LAN throughput is kind of offputting.
You should be getting much more than 30mbps if you're wired not wireless with default settings, but dd-wrt routing throughput is slower than stock firmware due to features. An e2000 should be somewhere around 60-70mbps with default settings and the only way it will achieve ~100mbps with dd-wrt is if your overclock it. _________________ Read the forum announcements thoroughly! Be cautious if you're inexperienced.
Available for paid consulting. (Don't PM about complicated setups otherwise)
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Posted: Mon Feb 21, 2011 19:33 Post subject: E2000 poor performance post-DD-WRT compared to stock
I'm having this issue as well. I was getting high 70 - 90 download speeds before DD-WRT, after installing DD-WRT (using builds 14929-big and 15962-big) I'm only getting mid-to-high 30's. I have gone back-and-forth a couple times to confirm that the observations are repeatable.
Any ideas or suggestions on tweaking any of the settings to improve this? I'm going back to stock if this is the best I can do.
I had similar problem with the wired connection. My internet is 120/10mbps and with build 14929 E2000 was able to download about 40mbps. I put back original firmware and speed is back to normal at 120mbps on LAN and about 55 on wireless.
Posted: Mon May 14, 2012 15:36 Post subject: 8Mbit
doesn't seem to be a problem on an 8Mbit connection. getting 7.8 and 0.78 up. within 2.5% or max speed.
i wonder what the cause of this is. i'd really like to know. btw i run wrt160n and 2x e1000v2 using newd2-k26 17201. anything newer doesn't translate/NAT my subnets across the WAN :\
i'm guessing the problem is iptables. too much throughput is probably causing overload of the cpu while applying rules. just a guess. faster cpu maybe, or maybe it's just too fast for any personal router to handle using iptables.
easy way to test this might be to put another router in the chain with a firewall, and disable the firewall on the dd-wrt. also, would have to turn it into a router and not gateway mode, so it doesnt do NAT. have the other router do the NAT.
you might also be able to monitor the cpu load in dd-wrt while performing a transfer.
I searched Google and found that neetdev_max_backlog is a Linux TCP tuning setting that basically increases the queue size of incoming packets (syn requests) waiting to be processed by the next TCP Receive process.
While increasing this does allow for more packets to be queued before being dropped, there is still a limit to how fast the hardware ca process the packets. Here are my results.
I also tried to set netdev_max_backlog to 2000 or 4096 with no change in performance. Checking top during these tests, I found the CPU load to be maxed out from the SIRQs or Software Interrupt Requests.
I did these tests just to figure out how much routing performance this router could handle with DD-WRT. With QoS/HFSC enabled, the CPU becomes pegged at the max I could get out of it was about 38Mbits/sec.