4 Core with AQM vs 2 Core with MultiThreadin, AFE, NAT
MediaTek MT7621AT has AFE and hardware accelerator for NAT and doesn't have AQM. IPQ4018 /IPQ4019 has AQM support and doesn't have AFE/NAT
How much difference it makes ?
Would Qualcomm Atheros IPQ4018 /IPQ4019's 4 cores and AQM negate make a difference of NAT and AFE?
When using NAT accelerator I have to disable SQM
MT7621AT: Not support native MU-MIMO technology. Support up to 3x3 MIMO. Up to three spatial streams simultaneously. Doesn't handle MU-MIMO transmissions where multiple clients are served concurrently. While it can support multiple spatial streams (e.g., 3x3 MIMO), it cannot utilize those spatial streams to simultaneously serve multiple clients with independent data streams. In other words, it cannot take advantage of MU-MIMO's capability to serve multiple clients concurrently using different spatial streams. SoC is limited to traditional single-user MIMO (SU-MIMO), where it can transmit and receive multiple spatial streams to enhance the performance of a single client device.
IPQ4018/IPQ4019: SoC support MU-MIMO technology up to 2x2 MIMO for both 2.4 GHz and 5 GHz bands, enabling simultaneous data transmission to multiple devices.
If you are asking for opinions on the two, I would very firmly be on the side of the mt7621 RT-AX53U.
I have a lot of MediaTek experience and have become a big fan. The IPQ4018 is likely a bit beefier on the CPU side. It's a quad core ARM where the mt7621 is a dual core MIPS with 2-way multithreading per core. That said, neither of them are particular CPU heavyweights, and the added RAM in the AX-53U will do you far better in the long run than two more marginal cores. And MediaTek SoCs maintain very good stability under load. This is because their AFE's offload the signal processing so if the SoC gets busy, it doesn't affect the WiFi signal.
The only negative factor is USB 2.0 only on the AX53U. Even there, though, the max transfer speed is on the order of 50MiB/s, which is still respectable.
HW acceleration reduces NAT CPU load to essentially nothing on the MT7621AT and increases its NAT throughout from ~500 Mbps to 1 Gbps, but only if you can use hardware acceleration. It is not compatible with SQM/QoS for example.
The RT-AC58U is a bit light on memory - only 128MB - and ipq401x has a history of vlan configuration issues. If you choose an ipq4018 device, I would choose one with at least 256MB of memory.
If you plan to use SQM/QoS, MT7621AT and ipq4018 targets make good, affordable, basic gateway WiFi routers for modest ISP connections (~200-250 Mbps ). If you have more than basic use in mind, I would choose a target with a more capable CPU and more memory, e.g., MT7622 or Filogic; or a separate router (e.g., NanoPi R4S 4GB), switch (e.g., Netgear GS308T) and AP (e.g., an RT-AX53U) setup.
This question is impossible to answer without knowing what software you want to run. Some software needs lots of CPU, but not much memory, and vice-versa. Some software needs lots of CPU and memory. Some software (e.g., Wireguard and fq_codel/simple SQM/QoS) can make good use of multiple cores, in which case the ipq4018 will perform much better than the MT7621AT. Some software (e.g., CAKE SQM/QoS and OpenVPN) can only run on one core anyway, in which case the ipq4018 will be a little faster, but not a lot faster.
I'm thinking of sharing a 500/500Mbit fiber-connecton between multiple "homes", let's say 2-4.
I assume I could assign each with a VLAN or assign each with there own subnet for LAN separation.
Should I go for VLAN or just subnet?
I wonder if RT-AX53U is a acceptable choice. Will VLAN / multiple-subnets be handled by the HW-switch or by the CPU?
I assume I should prioritize HW NAT over SQM/QoS, even though I would be nice to be able to provide every home with a minimum bandwidth, but I wonder how big the issue is in practice when the internet connection is so fast, let's say in case one user do heavy download.
It's fine if each get 200Mbit performance.
What about a "cheap" L2 managed switch like e.g. Netgear GS108Tv3 for about 75$. I wounder how the performance will be if you enable "Advanced QoS"?
Or Teltonika RUTX08 with an Quad-core ARM Cortex A7, 717 MHz. (for about 120$)
I don't think that is a good choice. SQM/QoS is going to be important for smoothing out half Gig symmetric ISP service split to multiple homes. The MT7621 and IPQ4018/19 CPUs are not fast enough for that. You need a MT7622 (just adequate) or faster CPU to handle this.
A managed switch to add physical Ethernet ports is a good idea if you pair it with a capable dual port router like a NanoPi R4S that has a fast CPU, but the CPU in a managed switch is going to be much too slow to handle routing, much less SQM/QoS to control latency. I think you'll need a fast CPU for what you're planning to do.
For around the cost of a switch and R4S, I second frollic's recommendation. A multi-port x86 router (e.g., with an Intel N5100 or 5105 CPU) would work out well.
Here is what it has to say about Netgear's: "It is possible to make things worse by applying only a few of these techniques, a classic example of this is in NetGear’s current QoS system which allows you to rate limit but holds the fifo queue lengths constant, and does not apply either packet scheduling or AQM, leading to exorbitant delays."
The bottom line is that doing this "right" (with CAKE or FQ_CODEL) takes MUCH more CPU than you will find in a managed switch. And for more than 100-200 Mbps, it takes more CPU than a MT7621AT.