Asus GT-AX6000 2.5Gb speed issue


New Around Here

I recently got 2.5Gb fiber internet, that came with a ISP Modified Sagemcom F@st 5670 router, it's pretty meh feature wise(no bridge mode unfortunetly and can't seem to turn off UPnP), but i do get +2200Mbps from speedtest using a 2.5Gb nic on the Desktop PC.
So i bought the Asus GT-AX6000 router, using it with latest merlin release and DMZ set to it's IP in the ISP router.
When i run a speedtest inside the asus router, it gives me the same speeds i got from directly connecting to ISP router.
But when i run the same speedtest to the same server from the desktop PC, i never get over ~1800Mbps, and if i have QoS on it goes down to ~950Mbps
Any reason for this or a way to fix it?


Tech Junky

Very Senior Member
Don't use the app in the router. Use a device through the router for accurate speedtesting. The CPU on the router can't handle the speed / app. QOS isn't needed unless you have a low bandwidth connection.

Turn off any apps on the router you won't need if you want the max throughput. Off the shelf routers can't handle all of the "perks" that companies add to them. There's a reason they're "cheap" in comparison to more robust enterprise or SMB solutions. If you want true performance bump to SMB or DIY w/ a PC setup.

Since you're paying for 2.5GE fiber it might be a good idea to step up to a custom solution instead of Asus. I run my DIY setup with a 5GE card inside to make sure I'm not leaving BW on the table. It also serves as a NAS and pushes 400MB/s over Ethernet. Over WIFI using an AP - NWA210AX I can hit 1.5gbps to the NAS. The box also speed tests on a 1gbps plan up to 1.5gbps with the over provisioning on the service.

If you want to setup a DIY solution you need at a minimum of a SFF PC with a PCI slot for a NIC that supports 2.5+ and there's a dual port option for ~$60 ( RTL8125 ) or a 4-port for $136 ( QXG-2G4T-I225 ) and then throw pfsense or linux on it to make it act as a router. From there you can add apps to monitoring / testing that will actually function. If you want historical data you could track performance with other apps/.


Senior Member
For the DYI setup PC, I highly recommend getting Intel-based dual or quad port cards. You can get them pretty cheap on eBay (but watch out for fakes).

Tech Junky

Very Senior Member
The problem with Intel is they don't do much in the nbase-t realm at a cheap price. The 4 port qnap is Intel based. The 5ge option they have is aquantia based.

I update my kernel weekly and every once in awhile have to roll back because the driver modules get dropped from the new kernel for some reason and then added again on the next release. When it breaks it just takes 5 minutes and a livecd to fix it.


New Around Here
thanks, I might actually do this, I did build and manage custom Linux gateways in the past.
for now until I get what I need, I have my PC's 2.5 port connected directly to the ISP router, and the ASUS mesh setup to a 1GB port on the ISP router so the rest of the devices keep working,
also have a 2nd 1gig NIC on my PC connected to the ASUS so I can communicate wish stuff on that network.

what I don't get is why the speed test inside the ASUS gives me an "ok" speedtest but the PC connected through it only get 1.8Gb max

Tech Junky

Very Senior Member
There's a lot that goes into a proper speed test though. I use a Linux script to get true numbers since all of the other web options have a huge spread of numbers and don't typically test long enough to get an accurate speed result. They also don't seem to properly geo locate the test server properly as well.

The Asus has some issues when going beyond 1gbps on the WAN from what I've seen around here. It could be related to the CPU in the device not being able to process the NAT quick enough to get higher yields. It's typically just a lack of resources that hobbles consumer network devices. I had an issue awhile back and had an Asus sitting in a box from a prior upgrade and pulled it out to use with my new 1gbps CM and it just fell on its face for performance w/ gig ports and AC WIFI. IIRC it only hit 300-400mbps even when wired.

I went through a couple of routers trying to hit my max speeds and ended up using a R7800 for awhile before taking matters into my own hands and hosting off a QNAP QWA-AC2600 card using hostapd. Worked great but, wanted to play with AX and there still isn't anything on the market for that sort of use so, switched to an AP ( NWA210AX ) and hit over 1gbps with that. It has sufficient resources even under load as it's more of an SMB class AP.

Nice thing about network gear is it tends to be easy to resell when you change your mind on what you want to use.

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