Internet speed of 1 gbps not reached?

[guaranteedsales]

I am looking for an explanation about internet speed reading on my system. I am running a Dell Optiplex system with 8 gigs ram and Intel CPU.
My provider is supplying me with a speed of 100 mbps which I was able to read on manny speed testing services. Reading from the eithernet connection, not the wireless, I was showing close to 100 download and the same for upload. I was then offered a further update to speed to 300 and to 1 gbps. I do see a speed increase but can not read past the 100 first obtained. After the update I had the provider place there own modem/router, a TP Link, ADSL with up to 5 k capable. When he uses his Dell laptop and reads the sp3eed it shows on his meter at 900 plus mbps.
I have the eithernet connection with cat5 into a D-Link 1 GB speed 10/100/1000 network card. I still only see the original 100 reading.
When I ask why I get no real answer just that thee equipment reads it and my doesnt.
They have been a great company and provided well for several years and also have no cap on usage.
My question is just what am I missing in my search for the 1 Gbps reading. Any reasons I cant see it and they do.
Any insight would be appreciated.

Link-local IPv6 address: fe80::cd3a:8d78:21ff:dea5%25
IPv4 address: 192.168.1.121
IPv4 DNS servers: 66.38.2.240
8.8.8.8
Primary DNS suffix: nctc.com
Manufacturer: D-Link
Description: DGE-530T Gigabit Ethernet Adapter
Driver version: 8.4.907.2012
Physical address (MAC): 0C-B6-D2-B2-A9-F1

router
TP link 34b6-2

 

[kanewolf]

Usually if you have issues with your wired network negotiating a gigabit link, your cable is the problem. Get a brand new cat6a cable and retry.

 

[shknawe]

Try this test it probably wont show full 1gbs, that's what I have, because isp dosn't send that big of signal but should show up to 300-500 so at least you know its pushing through.https://www.speedtest.net/apps/desktop