last time my router 100mbps, max also 93, 94mbps, task manager already show 100% netowrk usage

Yes normally you will slightly more than subscribed. Looks like this is a more conservative tune. A variance of about ±5% is typical amongst ISPs but for Unifi this is rather uncommon. Get a technician to come configure again maybe.

Wait a minute, TP-LINK AX6600.right? I assume the 2.5G port is used for WAN, and you connected wired or wireless? The 3 LAN port is only 1G ports so 930+ is normal take into consideration of internal lost.

Assuming, your router is Archer GX90 as TP-Link has a fewAX6600 rated routers...
1× 2.5 Gbps WAN/LAN Port
1× Gigabit WAN/LAN Port
3× Gigabit LAN Ports

The connection between the ONR/modem and your router will be 2.5Gbps BUT the connection between your router and your PC will be limited to 1Gbps.

When the LAN ports are all 1Gbps, the max speedtest results will be  ±940 Mbps.

No, both your router's LAN ports and PC network interface must be 2.5Gbps.

Eg. this router's specs below...
1 x 10Gbps for WAN/LAN ------to ONR/modem ✔
1 x 2.5Gbps for WAN/LAN ------to ONR/modem ✔

1 x 10Gbps for LAN -------to PC ✔
3 x 2.5Gbps for LAN -------to PC ✔

1 x RJ45 10/100/1000Mbps for LAN -------to PC ✗

Not just your card. It's the 1G port on the router too. Your speed is limited by it. Nowadays there are plenty of cheap 2.5G switches from AliExpress. It's something you can consider if you ever consider getting wired connection to your devices, ie wifi 6E/7 APs, computers etc. But kinda moot because you only have a single 2.5G port.

You need to buy a new router with 2.5Gbps or faster LAN ports and a 2.5Gbps network interface card.
Eg. for TP-Link the only router that has 2.5Gbps or faster LAN ports is the Archer GE800.
1× 10 Gbps SFP+/RJ45 Combo WAN/LAN

1× 10 Gbps WAN/LAN

4× 2.5 Gbps LAN  <<<================

What is the exact model of your router?

You need a new router.

This router only supports 2.5Gbps on the WAN side.
It only has 1Gbps on the LAN side.

1× 2.5 Gbps WAN/LAN Port <<========= ✔
1× 1 Gbps WAN/LAN Port

BUT

3× 1 Gbps LAN Ports  <<=========== ✗

Just want to share some info regarding this matter because I already saw the current internal pdf for the current offer. Some nice and polite TM staff from TM point showed me.

The 300Mbps RM99 (excl. tax) and 1Gbps RM159 (exl. tax) are part of Tier 3 and Tier 4 offer. TM made these Tier 3 & 4 offers specifically to counter offer Maxis or other customer that want to switch to other ISP.
I saw only 300Mbps and 1Gbps on the table for Tier 3 & 4. Other speeds are left blank, means no offer.

I saw some keynotes below the table stated that after 2 years contract finish, The Tier 3 & 4 offers will auto change speed meaning 300Mbps will become 100Mbps for the RM99 (excl. tax) and 1Gbps will become 500Mbps for the RM159 (excl. tax) packages respectively. So that is the catch for Tier 3 & 4.

For the Tier 2, it is the normal SWU we already know about. For example , if 300Mbps RM129 (excl. tax) will be reduce to RM119 (excl. tax). But this Tier 2 package will come with the postpaid Unifi mobile plan RM39 (excl. tax) per month and you have to pay first month whether you want to use it or not and can cancel it after the 1st month. And also includes the free 6 months and new router.

I don't read the whole pdf so I don't know the further difference in detail between Tier 3 and Tier 4. Maybe some TM staff in here can shed some light if they want to expose themselves 

So thats it, choose wisely before making any decision.

Ok you mention you got upgraded to 1Gbps
what Modem did you get, is it the black D-Link?

If no, then your modem probably has a max speed of Gigabit Ethernet = 940Mbps max

if yes, and assuming you used Double NAT or Bridge (this mode has a bug of randomly dropping to 300Mbps max) to connect to your TP-Link's 2.5Gig WAN Port

It is mentioned you have a Gigabit Ethernet Port
and the only ports left on the TP-Link are Gigabit as well

so again, 940Mbps max

If you have an advanced high end Wifi 6 client, maybe can pull over the 940Mbps barrier, but hard

each Ethernet frame have protocol header.
each IP frame have protocol header.
each application packet have protocol header.
those will take some space in addition to your actual user data payload.

unless your router AND LAN card are both capable of 2.5Gbps, at most you can get is 940Mbps.
if using Wifi, still have to check whether both sides are capable of communicating at higher capacity.

Depends on your area OLT, 10G/2.5G equipment on my side rarely can pull over 900 nowadays but back at my old parents place in Ulu Tiram with Alcatel Lucent can pull 1040Mbps even when network is not completely quiet

You will never notice that extra ~60Mbps bandwidth most of the time, TM won't bother to help you get the extra as they're trained to just approve anything beyond like 90% of the advertised speed. If you want to spend the extra money to chase the bandwidth down, be ready to spend money as 10G equipment is cheaper than 2.5G equipment, and you might or might not get screwed over by the OLT that your fiber ONT is connected to

TP-LINK AX6600 that router 1GBPS Lan port hahaha
2.5GBPS = WAN PORT but LAN PORT ALL ARE 1GBPS no there LAN PORT 2.5GBPS

you noob ???
1× 2.5 Gbps WAN/LAN Port
1× 1 Gbps WAN/LAN Port
3× 1 Gbps LAN Ports

1x 2.5GBPS WAN Port = ONR/MODEM only
3x 1GBPS LAN Ports = PC you won't get 2.5Gbps
if you buy PCIE CARD 2.5Gbps but you router is 1GBPS Port lan

1 Gbps Lan Ports = PC 2.5GBPS = you get 940Mbps wont go over 1GBPS understand

get new router buy now and pcie card 2.5gbps
setttle

Just got my free upgrade (800mbps-1gbps)on 3rd sept 2024
Got the D-Link Model no : DPN-FX3060V  (black) old firmware v1
Cat7 + 2.5port on dlink connected to my 2.5 lan motherboard(auto nego with 2.5gbps) = 940-950mbps only
make a report and 1st lvl technician came on 5sept but failed to fix the issue reported which cant get >1000mbps
technician filed report for EC team (higher lvl)
Ec team (unifi elite)came on 9sept and do diagnose which is changing router / open higher OLT / upgrade firmware
Problem fixed

Got constant speed >1000mbps ( average 1040-1060mbps) now with the free router DLINK DPN-FX3060V (Firmware ver:DPN-FX3060V_V2.0.3)
Based on the technician need to use the v3 firmware and some configuration on cabinet side
My area using Huawei Infra

technically yes it is, since the lan port 1 is 2.5gbe port(make sure its v3 firmware)
BUT
make sure on your side you using at least cat6 cable & your device (pc/laptop) network card is also 2.5Gbe
AND ALSO
depend on TM infra in your area is it capable or not (this part is easy, just keep on lodge report until they solve it)

I'm using SWU 2.0 right now and gonna expired next month...
It is possible for me to get SWU plan again?

if tm counter no offer ?just walk away?
then switch maxis get transfer ID ,visit tm point 2nd times ?
how about swu 5.0 for 300m and 500m package

thanks ...

SWU5.0 release?
Anyone can list down the actual price?
Current plan RM129 300mbps is time to upgrade speed.