internet speed slow from router to core switch

[netacaduser575395547]

Hi

 

we have cisco 2921 router connected to core sw and internet from the ISP, the issue is that the internet from the core sw is about 150kb while from the router is 10mb.

after a lot of testing, I disconnected the router and connected another similar router with only basic settings such as NAT.

(I didn't want to miss up the production router as it has many settings that I don't know)

the internet speed was perfect, some host got 6mb to 9.5mb. So what could be the issue with the router I disconnected?

I have attached the diagram of our network which start with only 10.x.x.x and the current configuration for the router.

[Ramblin Tech]

Did you happen to capture any "show interface" output before swapping out routers? A snapshot from both sides of the link could give an indication as to whether there are any transmission errors.