Fix: Slow network file transit with Windows Vista/7

I noticed my network file transfer speed was much slower when moving files from my NAS to my Windows 7 box, when compared to moving the same files to my XP machine. Both my XP machine and Windows 7 machine have gigabit NIC’s, the DS-408 NAS also has a gigabit NIC, and they are connected together via a gigabit switch. The problem it seems is my Windows 7 machine only connects at 100Mbps instead of 1Gbps. I did some tinkering and in the end managed to tweak my settings to achieve maximum throughput at 1Gbps full duplex.

Step 1. Disable the Remote Deferential Compression (RDC) feature which is automatically enabled with Windows 7.

1. Click ‘Start’, ‘Control Panel’, ‘Programs’, ‘Turn Windows features on and off’
2. Clear the check box next to ‘Remote Differential Compression’ and click OK.
3. Restart your machine

You should notice some difference.

Step 2. Turn off IPv6 Support

As most software and equipment still do not support this i see little point having it enabled, in fact it seems disabling it can improve performance.

1. Click ‘Start’, ‘Control Panel’, ‘Network and Internet’, ‘Network and Sharing Center’, ‘Local Area Connection’ and click ‘Properties’
2. Enter admin credentials if prompted, otherwise click continue on the User Access Control (UAC) prompt
3. Clear the check box next to the ‘Internet Protocol version 6 (TCP/IPv6)’ component
4. Click ‘OK’
5. Click ‘Start’, enter ‘regedit’ into the search box and press enter to open the Registry Editor (UAC prompt again, see step 2)
6. Navigate to ‘HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicestcpip6Parameters’
7. Create the following registry DWORD value ‘DisabledComponents’ (enter exactly as shown, it is case sensitive)
8. Open the new DisabledComponents entry and set the value to 000000FF
9. Restart your machine so the changes can take effect

To revert these changes simply re-check the IPv6 component and delete the DisabledComponents registry entry, or set the value to ‘0’

Step 3. Power cycle the Switch/Router

If all else fails and your gigabit network still connects at 100Mbps speeds, unplug the patch cable from the gigabit switch to the router, check the connection between the PC(s) and the switch, power cycle the switch and reboot the PC(s) on the network. Once you’re connected again at Gigabit speed you can reconnect the router / slower devices. The idea here is too establish the network with the Gigabit devices 1st, and then connect the slower (fast-ethernet) devices.

If you’re still not connecting at optimal speed check the cables for degradation, and ensure your only using Cat5 or Cat6 patch cables.


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