New laptop on work network - slower to save files than previous laptop

Wired connection.
Connection to work network, imagine its T1.

I cant run any of the config tests etc as my pc is locked down for administrators only as its a work pc.

My question:
I previously had a lenovo laptop T420 or something which worked fine, but it was 4 years old so my company changed it for a Lenovo X260. Quicker processor, SSD etc.

Anyway, now it takes me longer to save files to the network server when in MS office apps, or even copy and pasting files from within windows explorer.
I timed one 8mb excel file - old laptop took 3 seconds to save, the new laptop 53 seconds!

The IT department are looking into it and have checked loads of settings and reckon its the same. user profiles etc etc, updates etc. But clearly the problem is there.
My colleagues too have the same problem, all but the one person who is still on the old laptop.
I am told we arent on a a gigabit lan, but then that hasnt changed between laptops either.

Any ideas of what i can or suggest them to check? they are pretty much saying get used to it, which is fine when people arent using massive excel files all day!

Welcome to the forum. It could be anything what about antivirus that can do as it scans on read and write saving files could be network not getting right settings

Antivirus (symantec endpoint protection) has the same settings on new and old laptop.
I know it could be anything, but im trying to get a list of things to check.

On the previous laptop when i saved a file you rarely saw a dialogue box appear, but not its everytime, i.e. the window pops up saying its saving, and shows the speed. 256kb/s.

They tried changing the auto negotiation setting on the network adaptor(?) but no difference.