Slow computer-computer wired LAN speed on new RT-N66U

[KenOp]

Just installed a new RT-N66U router. I'm very, very happy with the wireless range and speed. But when trying to run a program that uses data from another computer on our home LAN, the program took forever to load (> 1 minute compared to about 5-10 seconds previously).

In performing some tests on both computers, it seems that transfers in one direction are very fast (~ 70-80 MB/s), but transfers in the other direction are horrendous (< 5 MB/s).

The RT-N66U firmware is 4.276. One computer is running Win 8.1, the other 8.0. The only change made was swapping routers. Before doing so, transfers in both directions were acceptably fast.

Any ideas? I'm really stumped and can't even think of where to look / what to try.

Ken

 

[RMerlin]

If either (or both) devices are wired, try replacing the Ethernet cables. I've had issues like yours in the past with a poorly crimped Ethernet cable - I would get a lot of packet losses in one direction.

Make sure cables are rated Cat5e or higher.

 

[GlendaPeter]

Speed Up Internet speed

- Log on as Administrator
- Start - run - type gpedit.msc
- Expand "local computer policy"
- Then expand "administrative templates"
- Then expand "network branch"
- Highlight the "QoS Packet Scheduler"
- On right window double click "limit reservable bandwidth"
- On setting tab check the "enabled"
- Change "Bandwidth limit %" to 0
- Restart PC

Hope so after performing these tips your Internet speed will be increased. If Not! Then I would suggest you to download Reginout and optimize your internet speed with simply one click. Hope it will works.

 

[KenOp]

Thanks for the replies.

RMerlin, excellent idea. As the title suggests, both computers are using a wired connection to the router. I replaced both cables, but sadly no difference. They are Cat 5e, but that points out a difference between the routers. Our old router had 10/100 ports, while this one has gigabit ports. Both computers have gigabit adapters.

GlendaPeter, this isn't an internet speed issue, but in case it made a difference, I gave it a shot anyway. But even after rebooting, it didn't change the symptom. Thanks for the suggestion.

I also tried using different ports on the router, just in case, but no joy.

 

[wouterv]

Maybe Auto-negotiating between the PC NIC and router port plays up.
Open the network adapter properties > Configure > Advanced, look for the "Speed and duplex" setting and set it fixed to: 1 Gbps / Full duplex.

 

[KenOp]

Thanks wouterv, your post has really helped.

1. The problem is not router-related.
2. The problem seems to be the gigabit controller in one of the computers.

I hooked up another computer to our LAN, and my computer could copy from or write to the other computer at a sustained rate of 110 MB/s, according to Win 8.0's copy dialog. The other computer (my wife's) could only manage about 5 MB/s.

The odd part is, in trying your suggestion, her card could be set to 1 gbps / full duplex, but mine only offers 100 or 10 kbps (in addition to auto negotiate). But clearly it is a 1 gigabit card, based not only on the name it displays, but also by being able to copy at a sustained rate of 110 MB/s.

Also strange, when we set both of our cards to 100 kbps / full duplex, we could not copy files in either direction (though we could see each other's drives and folders). Weird.

So, time to buy a gigabit card. Unless I can find an updated driver for the controller built-in to the mobo, but it's pretty old so I doubt it.

Thanks again!

 

[wouterv]

Usually you can find updated drivers for way old network adapters.
I suggest to not try to search through Window Update (many bad experiences with the updated drivers offered by Microsoft).
The best is to check the computer vendor website for driver updates, those drivers should be tested with the specific computer hardware configuration.
Second best is to look at the NIC or chipset manufacturer website (e.g. Intel or Broadcom or Realtek).
Luckily these days Windows offer an easy driver rollback in case the "new" driver is worse then the "old".

 

[KenOp]

I did find an updated driver on Realtek's website (though it was only a little more recent than the installed one). Unfortunately, it didn't improve the situation one bit.

I also found an old Intel 10/100 NIC lying around, and installed that one. It works MUCH better -- in fact (not surprisingly) exactly as fast the built-in Realtek used to work with our older (10/100) router.

So we could just keep using the 10/100 NIC, but it would be nice if I could increase our cross-computer speed by almost 10x. Worth buying a gigabit NIC, IMO.

Thanks, and again thanks to everyone who helped. Everyone here is always so willing to help, and I really appreciate it.

 

[RMerlin]

Some of Realtek's low-end integrated stuff is really bad. Gigabit performance is highly unreliable here with my Zotac HTPC under Linux - there were a lot of references to that particular NIC model, Linux and poor SMB performance, for some odd reason.

 

[KenOp]

This is a 6 or 7 year old abit (AB9 QuadGT) motherboard, so it wouldn't surprise me at all if the Realtek chip had problems with gigabit speeds on most of them, under any OS. And if they haven't fixed it by now with the driver, it obviously is hardware related.

But nothing a good $30 Intel NIC can't fix.