Can't get 2.5Gbps on RT-AX88U Pro

[Mox]

 Hey everyone, I'm new here. I looked for a specific Asus forum and this seems to be the best one for helping me. I checked for similar discussions, but none seem to match my situation or a similar case.

 I have an RT-AX88U Pro, and a 2.5G FTTH fiber connection that ACTUALLY reaches 2.2-2.3Gbps, confirmed also in speed tests done through the Asus router's GUI or app (powered by ookla).

 I have an Intel NUC with a 2.5G port, and a MacBook with a 2.5G USB C Ethernet adapter. Both were tested and working at around 2.2Gbps when connected to a ZTE router (same modem provided by FTTH provider).

 However, when they are connected to my Asus router (which, as mentioned, confirms 2.3Gbps internet speed, via its internal speed test in QoS section), they can't go above 1.2-1.3Gbps, even though they are connected to the 2.5G LAN port (not at the same time, there is no switch in between), and both the router's GUI and the network settings of these devices confirm a 2.5G connection.

 Basically, everything seems to work perfectly... except for the actual final speed of my devices when connected directly to this router (with various cables, all very short and suitable for 2.5G), while they reach also 2.3Gbps when connected to a ZTE router (exactly the same configuration).

 Whether I turn QoS on or off nothing changes (maybe just a bit better with QoS off).

 I really can't explain this. Does anyone have any ideas? Thank you very much.

[jzchen]

• I have had poor speed with QoS turned on, so I would leave that off for now.  Have you tried enabling Jumbo Packets to see if that helps?

[Mox]

Is this still possible on the new Asus router's GUI? I read that's no longer possible, similarly to NAT Acceleration. I'll try this, if it heps with AiProtection too.

[jzchen]

I found it, on a different BE router but also running 3.0.0.6.xxxxx under:

Advanced Settings -> LAN -> Switch Control (tab)

Worth a try IMHO...

Disappointed that AiProtection has such big overhead.  There was an update within the last couple of days.  If I recall correctly 2.450 (could be off)...

[Mox]

As far as I can see I've the last firmware version, and in Switch Control tab I only see Link Aggregation option.

[Mox · Accepted solution]

   Hey, just answering my own question because I figured out the problem, and maybe it'll help someone else: the real culprit is AiProtection by Trend Micro.

   You can turn it off completely (or just parts of it) in the router's settings. Actually, I turned off everything: QoS, Traffic Analyzer, etc., and my speed jumped from 1300Mbps to 2300Mbps. But the last thing I disabled that really made the performance leap was AiProtection.

   Apparently (from what I found out), turning these features on disables NAT Acceleration, you can't directly control it anymore. Just having these features on makes the CPU the bottleneck (I guess).

   They say that if you turn on Advanced QoS, the problem shouldn't happen (but it does with Traditional QoS), but with this much bandwidth, I'm not even sure it makes sense to use QoS.

   On the other hand, AiProtection seems useful, so I don't know...

[jzchen]

AiProtection update 2.456 is out today.  Running it on an AXE11000 as it is a router at my in-law's place.  1 Gbps fiber there...