Unstable bandwith with T42S/T46S

[SD321-GYHS]

Hello,

We will deploy some T46S, T42S in our network but we encounter some bandwitch drop when our computer is plugged via the phone.

Our network is in 100Mbps, so the "internet" interface is in 100Mbps but between "PC" interface and the computer, there is a gigabit link. When I test the connection, our bandwith drop to 30-20Mbps~

If I force the network card negotiation of my computer to 100Mbps, the bandwitch doesn't drop (95Mbps~), and if i force the "PC" interface of the phone to 100Mbps, the bandwitch drop more than usual (5Mbps!)

Obviously, the 46S/42S has some problem to manage the bottleneck between the gigabit "PC" and 100Mbps "Internet" interface! And the phone's bandwitch is more instable when we force "PC" interface to 100Mbps.

We didn't notice encounter any problem with the T41S model ("PC" interface is maximum 100Mbps in this model)

For some reason, is difficult for us to reconfigure all network card's computer to 100Mbps... So there is a solution to fixe this problem?

Firmware: 66.83.0.20
Note: sorry for my bad english, i'm not native english speaker.

Best regards,
Gary.