I was wondering because when I did heavy youtube viewing in the summer holidays on the school laptops it was fine but that was only 8 or 9 machines.

 

Guess when i get the chance i'll see if i can offload some of the network onto the other router.
(Spent the last week trying to get through diagnosing an issue with an email account but kept getting interrupted with other work.)

How about a Bosch 1619EVS.

 

Oh wait, wrong type of router.

To be honest, we could probably do with one of those too.

Is that a wireless router?

Yes, but pretty much all the wireless connecting goes on with an access point in another part of the building.

 

Not the full network but this will give you an idea:

 

Access Point-------Switch-------Router
|
|
Other Office switch

I'm with you - it could certainly be your router, but I think you need to spend a little time narrowing things down between other devices.

 

Though as Ant says, could easily simply be your internet speed. That said, to be fair, day to day internet use doesn't use quite as much as you'd think. I know of places with 500+ machines using 10mb - 20mb with no drama. But then it does depend a lot on the quality of your connection, contention rates etc etc.

If your router and switches provide SNMP access, get hold of the free version of something like PRTG and get some bandwidth monitoring going.