Understanding WiFi-Performance with OpenWRT compared to OEM firmware

[Starbase12]

Hi,

I want understand how OpenWRT affects the WiFi performance. I'm having two TP-Link Routers available. Archer C7 and a C2600. The C2600 should provide max 1733 Mbps with 5 GHz and 800 Mbps when using 2.4 GHz.

Effectively with OpenWRT it seems to be limited to around 300 Mbit/s.

Is this a general disadvantage of using OpenWRT? Did I choose a non well supported wifi chipset?
Maybe other devices can deliver a faster connection?

Thanks in advanced.

[frollic]

@Starbase12

The C2600 should provide max 1733 Mbps with 5 GHz and 800 Mbps when using 2.4 GHz

as you were told on reddit, these are theoretical and/or lab values nowhere near real life.

[slh]

It very much depends on the details - and the exact devices, but in the end you can only test it 1:1. There can be differences (different drivers, different levels of offloading, etc.), but there don't need to be.

@Starbase12

The C2600 should provide max 1733 Mbps with 5 GHz and 800 Mbps when using 2.4 GHz.

Now you are raising marketing numbers, but not what's actually achievable in the OEM firmware either - faaar from it.

• first of all you have to distinguish between the established link rate (gross) and the actually achievable net throughput, this alone is typically half of the stated gross link rate.
  and we're down from 1733 to 866 MBit/s
• the you need to consider that this is achieved using all four antenna chains, but your typical mobile client (smartphone, notebook or desktop computer) usually only has two antennas, halving your figure again
  and we're down from 866 to 433 MBit/s

In practice, you will see 350-400 (maybe 450-) MBit/s for 2x2 802.11ac/wave2, which is in line with the above.

The same works the same way on 2.4 GHz.

[Starbase12]

Thanks for your explanation. The facts about the antenna chains are new to me. Of course I also know that marketing specs are mostly marketing specs.

Do I understand correctly that the 300 Mbit/s I'm able to get (tested with iperf3) is mostly not because of OpenWRT. More about my mobile device I'm using?
I should be able to compare the speeds with OEM firmware. Simply buying a more supported OpenWRT capable Router doesn't seem to help in my case.

[fakemanhk]

@Starbase12

I want understand how OpenWRT affects the WiFi performance. I'm having two TP-Link Routers available. Archer C7 and a C2600. The C2600 should provide max 1733 Mbps with 5 GHz and 800 Mbps when using 2.4 GHz.

You have to understand the "up to XXX Mbps" marketing strategy, and actual speed depends on your client, and/or environment.

For example, Archer C7 advertises 1300Mbps for 5GHz and 450Mbps for 2.4GHz, right? The 1300Mbps for 5GHz is based on 3T3R max. transfer rate, other than the older Macbook Pro (I think those selling in ~2015) there is no mobile client that can have 3T3R, mostly 2T2R only, so theoretical max. is already being cut down to 866Mbps. Same for 2.4GHz, theoretical max. is 300Mbps, but it's even worse here because 300Mbps 2T2R is assuming you are using 40MHz channel width, but in real world the noise and interference are too much (unless you live in middle of nowhere) that 40MHz is not usable, the practical usage is 20MHz width which gives you at most 150Mbps.

Oh, and this is wireless, some signal will be lost in air, also obstacles will block/absorb some signal as well, in real world even with a very good wireless router it's hard to get > 80%, placing your device in just 10cm apart from router getting 70-80% of the speed can be considered very good already, normally inside the same room without obstacle you are getting 60-70% only, with walls it will drop even more on 5GHz. So 866Mbps theoretical max. can give you probably 400-500Mbps at most in normal daily life, with a better designed antenna, signal can be transmitted more effectively, it's also possible to see ~600Mbps but I would say you can't get any more.

Now you can do all estimations, and those are UNRELATED to firmware, because wireless signal strength has a country regulated max., when it's configured to be used in certain country, no matter OpenWrt or OEM or any firmware there is no way to get more signal.

My example of Netgear WAX206, it advertised as 2402Mbps on 5GHz 802.11ax, in real world using 160MHz channel getting full 2402 link rate and laptop sitting next to router, I am getting roughly 1.3-1.5Gbps which can be considered very good already!!