Max Transit Duo Router Throughput

Hi guys, have a question about the rated router throughput of a Max Transit Duo which is stated at 400Mbps. I’ve been doing some testing with a 1000/100 WAN - If I connect the WAN directly to my laptop I can achieve the full 1000/100 when testing with If I go via the Max Transit Duo and do the same test I’m only testing around 250/100. The Outbound policy is set to enforced to the WAN and no traffic is going via speedfusion. I’m sure when I’ve done this in the past I’ve been able to achieve pretty close to the 400mbps limit of the router. Any ideas why I’m not achieving closer to 400 or any advice on what to check? Thanks!