I've just got in a new gigabit switch (this one, although it's packaged as a Tenda unit rather than a Plexus one) to connect up my 2 PCs. I have connected the onboard network card from each of my 2 PCs (Marvell Yukon 88E8056 PCI-E Gigabit Ethernet Controller in this PC and Realtek RTL8168C(P)/8111C(P) PCI-E Gigabit Ethernet NIC on the other (descriptions taken from Device Manager)). The drivers for the network cards are correctly installed on each PC, the Speed light on the connector shows 1Gbps for each card and the connection from within Windows Network Connections for each of the cards shows the speed as 1.0 Gbps. The switch lights also show the 2 connected PCs as 1000 Mbps. All good so far. However, I'm not getting the transfer speeds I was expecting.

When I send files from PC1 to PC2 (using a shared folder on PC2, copy paste into it from PC1) I'm getting about 22 MB/sec (this is semi-acceptable). When I copy files from PC2 onto PC1 (copy paste from a shared folder on PC2 onto a local folder on PC1) I'm getting 11 MB/sec (this is 100 Mbps range and not acceptable).

PC1 (this PC) is running Vista Home Premium SP1 32 bit.
PC2 is running XP SP3 32 bit.

Am I missing something stupid / do I need to do anything else to improve the transfer speeds?

Thanks in advance for any help or advice.

To get decent speeds over gigabit ethernet you should get some good quality network cards (not Realtek), integrated solutions often seem to be more or less crappy. Enabling jumbo frames might help if the switch supports them (the specs dont say so it might not, propably has a very small buffer as well since the size is not mentioned).

I use PCI Intel PRO/1000GT adapters an a D-Link DGS-1008D switch, they typically do about 600-800Mbps in practice.

I used these tools to speed up (read: unlock the potential of) my network connection. And yes, I'm using onboard network cards, but their performance is only limited by Windows, they don't have hardware limitations.

http://home.comcast.net/~SupportCD/OptimizeXP.html#Internet

Download and run the TCP/IP optimizer and the TCP/IP slowdown fix. For the optimizer, just set the connection speed to your modem's speed (mine is 7 Mbps) and click the "optimized" radio button at the button, apply and restart. For the other it simply unlocks the Windows-set MTU limit of 10 and you can change it to a really high number, something around 16,000,000.

These two tools greatly sped up my networking speeds, but you have to run them on all the computers in your house to achieve high speeds between all of them.

Don't you also need Cat6 grade cabling to achieve the most of out gigabit ethernet?

Quote from shiny_red_cobra :

I used these tools to speed up (read: unlock the potential of) my network connection. And yes, I'm using onboard network cards, but their performance is only limited by Windows, they don't have hardware limitations.

http://home.comcast.net/~SupportCD/OptimizeXP.html#Internet

Download and run the TCP/IP optimizer and the TCP/IP slowdown fix. For the optimizer, just set the connection speed to your modem's speed (mine is 7 Mbps) and click the "optimized" radio button at the button, apply and restart. For the other it simply unlocks the Windows-set MTU limit of 10 and you can change it to a really high number, something around 16,000,000.

These two tools greatly sped up my networking speeds, but you have to run them on all the computers in your house to achieve high speeds between all of them.

I'm not a fan of these "configuration" utilities, but thanks anyway.

Quote from Bob Smith :

Don't you also need Cat6 grade cabling to achieve the most of out gigabit ethernet?

All of the cabling is Cat5e or Cat6.

Quote from Kegetys :

To get decent speeds over gigabit ethernet you should get some good quality network cards (not Realtek), integrated solutions often seem to be more or less crappy. Enabling jumbo frames might help if the switch supports them (the specs dont say so it might not, propably has a very small buffer as well since the size is not mentioned).

I use PCI Intel PRO/1000GT adapters an a D-Link DGS-1008D switch, they typically do about 600-800Mbps in practice.

I returned the other switch (because of the Tenda branding and it didn't feel like a quality product). I got the above switch and 2 of the above NICs. I've installed them and I'm still getting disappointing performance. To try and diagnose the problem I've moved both the PCs to within a few feet of each other. Between PC1 and the switch there's a 1m length of Cat6 cable. Between PC2 and the switch there's a 3m length of Cat6 cable. I have gone into the advanced properties of each of the NICs and changed "Jumbo Packet" to 16128 bytes (i.e. I've enabled jumbo frames on both NICs).

When I copy files from PC1 to PC2 I get roughly 25MB/sec. When I copy files from PC2 to PC1 I get roughly 30MB/sec.

I've used the IPERF tool to benchmark the connection and I'm getting 191 Mbits/sec when I run PC2 as server and PC1 as client and 268 Mbits/sec when I run PC1 as the server and PC2 as the client.

Any thoughts?

Sounds odd, did you try other jumbo frame settings than the maximum? I have mine set to 4096, which seems to give the best performance overall for me.

Quote from Kegetys :

Sounds odd, did you try other jumbo frame settings than the maximum? I have mine set to 4096, which seems to give the best performance overall for me.

I've just tried the other options for frame sizes.

At 4088 bytes I get about 22-23MB/sec transferring from PC1 to PC2 (erratic speed, not steady) and 34MB/sec transferring from PC2 to PC1 (steady).

At 9014 bytes I get 22MB/sec transferring from PC1 to PC2 (steady) and 33MB/sec transferring from PC2 to PC1 (steady).

Here is a thread I created on a different forum to show the story to far. The abridged version:

I should have ordered PCI-E cards rather than PCI cards. I have contacted Scan and they're letting me RMA the cards even though it was my fault.
Vista can throttle network performance when you're playing media on a PC, so this can interfere with your bandwidth.
I've ordered replacement cards to arrive tomorrow (since Scan don't stock them), so I should (fingers crossed) have a big boost in performance then.