Does 8x4 Modem Router slows down the internet to 50Mbps if I get 400Mbps from IPS?

[Eva138]

So I got upgraded to 400Mbps complementary (to not cancel the service) from my IPS but the internet speed slowed down to 50 Mbps. When I had the 200Mbps, this modem truly supported up to 200Mbps. Now I supposed to get 400Mpbs from IPS but the actual speed went down to 50Mbps... I rebooted my modem but the speed has not been improved. I expected to get at least 300Mbps as the modem's product description says it can support up to 340 Mbps. I am wondering if this is due to the IPS or my modem. Anyone can help me? Do I need to contact IPS or get a new modem?

Thanks!

[DarrenM]

I would first check with the ISP to make sure they coded the modem to get the correct speed if someone went in and changed your speed they could of made a mistake and your modem is being told to get 50mbps speed.

DarrenM

[vkdelta]

Pretty much all the ISPs do not support >200Mbps on 8x4 modems.

even though product is capable and it would work in Lab, ISPs channel plan would not support close to 300 Mbps on live network.