1. check the cables makes sure there good
2. check link speed is not set to auto (make the speed of your router port speed)
3. disable any power saving mode
4. enable offloading (all of them) for the nic only
5. make sure router firmware is up to date
6. make sure drivers for NIC on the systems be up to day
7. make sure 7 is up to date
8. if okay go to 9 if not go to 10
9. For the Windows 7 network tweaks..
Below is my tweak after modification.
Querying active state...
TCP Global Parameters
----------------------------------------------
Receive-Side Scaling State : enabled
Chimney Offload State : automatic
NetDMA State : enabled
Direct Cache Acess (DCA) : disabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : ctcp
ECN Capability : disabled
RFC 1323 Timestamps : disabled
** The above autotuninglevel setting is the result of Windows Scaling heuristics
overriding any local/policy configuration on at least one profile.
Note: Same tweaks are used on 100mbps, 1000mbps, 802.11g, 802.11n.
To access this under Windows 7 do this:
Go under all programs,
accessories,
right click on command prompt click on Run As Administrator.
Type: netsh int tcp show global > c:\mysettings.txt
Exit out and go into the computer folder and pull out this file and open it in notepad. Copy and paste your results in the next reply back from you.
10.
If you done all, reset the router back to the factory defaults
Scan system for pest, registry errors, HDD fragmentation
Still nothing, un-plug the power on the router and modem and wait 30 seconds
Reboot all systems
Router could have duff ports (bad) try different ports
If still a no go try a different router.