Is this much difference in data speeds between 2.4 GHz and 5 GHz WiFi bands normal?

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I have a 100 Mbps WiFi connection. The 5GHz band gives a speed of > 100 Mbps upload and download using speedtest.net, which is great. The 2.4 GHz band, however, gives only a speed of around 30 Mbps, even if I stand next to the router. Note that I have disconnected all other devices from the network before conducting the speed test.

I am aware that speeds on the 2.4 GHz band are lower than that on the 5 GHz band. But a difference of 70–80 Mbps, that too standing next to the router, seems huge. Am I correct? I have called the engineers from the ISP tomorrow to relocate the router inside the house; I want to bring up this issue too.
 
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  • #3
It is much easier for a slower internet technology to become overloaded by multiple customers. The speed for an individual user is often much lower than the advertised maximum. As long as your computer is reasonably close to the router, the distance is not causing it to be slow. Try the speed test during off-hours (3 AM should be good) and see if it improves.
 
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  • #4
jedishrfu said:
Network speeds are affected by so many parameters it can boggle the mind.

https://superuser.com/questions/1557941/wifi-on-2-4ghz-is-slow-but-5ghz-is-very-fast
The person on SuperUser seems to have complained about the exact same issue. Though…
jedishrfu said:
talks about the more common 2.4ghz band being more congested with users and hence slower data speeds results vs 5ghz band with fewer users.
…when I did the speed test, I disconnected all devices from the WiFi network (on both bands), so congestion should not be a factor.

I don't have any device that normally requires using the 2.4 GHz band, except my laptop, which has a strange software bug in the OS (Ubuntu) and often cannot connect to the 5 GHz band all of a sudden. In that situation, I have to either reboot, or switch to the 2.4 GHz band until the next reboot (which is often days, if not weeks, apart). I am getting awful 5 GHz band signals, which is why I decided to relocate the router closer to where we mostly work now.
 
  • #5
FactChecker said:
It is much easier for a slower internet technology to become overloaded by multiple customers. The speed for an individual user is often much lower than the advertised maximum. As long as your computer is reasonably close to the router, the distance is not causing it to be slow. Try the speed test during off-hours (3 AM should be good) and see if it improves.
I am uncertain if I fully understand this. I have a fiber optic connection that goes straight into my router; I do not share the WiFi with any other house. The distance is definitely not making it slow because, as I wrote, standing just next to the router, the 5 GHz band gives > 100 Mbps, while the 2.4 GHz gives ~ 30 Mbps. The speed certainly drops over distance, which is why I am relocating the router, but apart from that, the 2.4 GHz band is unforgivably slow.
 
  • #6
Wrichik Basu said:
I am uncertain if I fully understand this. I have a fiber optic connection that goes straight into my router; I do not share the WiFi with any other house. The distance is definitely not making it slow because, as I wrote, standing just next to the router, the 5 GHz band gives > 100 Mbps, while the 2.4 GHz gives ~ 30 Mbps.
Are you saying that it is a totally local network? If you are testing download and upload speeds, then you are sharing a network with many other people.
 
  • #7
What happens when you turn one of the bands off at the router?
 
  • #8
FactChecker said:
Are you saying that it is a totally local network? If you are testing download and upload speeds, then you are sharing a network with many other people.
When I am testing the upload/download speeds, I am doing it over WAN. I can connect to servers all around the world for a speed test, so not local. But even if the WAN fiber optic connection is overloaded, at the time of testing, it still gave me 100 Mbps upload/download over 5 GHz, so it's fine.
Frabjous said:
What happens when you turn one of the bands off at the router?
It's currently 2 AM local time. With both bands enabled, 5 GHz gives a top speed of 70 Mbps at the moment (compared to 100 in the afternoon, when most people were out for work). 2.4 GHz gives 30 Mbps max. Disabling either of the bands does not affect the speeds seen by the other band.
 
  • #9
I also checked the router settings and found the 5 GHz channel spacing to be 20/40 MHz by default. Should I change this to 80 MHz? The 2.4 GHz band had a spacing of 20 MHz; I set that to 20/40 MHz.

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  • #10
Don't forget there are other folks nearby with wifi routers broadcasting on the same band and that can interfere to some extent.
 
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  • #11
(1) If 5 Hz weren't faster, why would anyone ever have developed it?
(2) 2.4 GHz is a lot more crowded, so speeds often have to be slowed down to get through the interference.
(3) How fast do you need it? Are you streaming multiple movies at once?
 
  • #12
Vanadium 50 said:
(1) If 5 Hz weren't faster, why would anyone ever have developed it?
Definitely 5 GHz is fast, but the thread is regarding the huge difference in speeds between the two bands, and whether that is normal. 802.11n interface can support speeds up to 150 Mbps per antenna, so if my current router has at least one antenna, the speed should be more, at least theoretically. For instance, ...
Vanadium 50 said:
(2) 2.4 GHz is a lot more crowded, so speeds often have to be slowed down to get through the interference.
...this is something I learnt from this thread.
Vanadium 50 said:
(3) How fast do you need it? Are you streaming multiple movies at once?
30 Mbps doesn't work for daily Zoom calls, unfortunately. That's why I am paying for a 100 Mbps connection.
 
  • #13
Ignore numbers like 450 Mbps. These are numbers that one might get in the lab under ideal conditions with no overhead. 30 Mbps is about what you can expect in real life - I just measured mine on that band only and get 29.

Or you could turn all of your neighbors Wifi off.
 
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  • #14
From what Intel says, you might expect an even bigger difference in speed between the two frequencies.

https://www.intel.com/content/www/us/en/products/docs/wireless/2-4-vs-5ghz.html

2.4 GHz vs. 5 GHz vs. 6 GHz: Difference in Speed​

In addition to channel characteristics, typical data transfer speeds are influenced by factors such as other devices using the band, physical objects or walls reducing signal strength, or limitations imposed by an internet service provider (ISP).

  • 2.4 GHz can deliver a typical over-the-air max speed of up to 100 megabits per second (Mbps).
  • 5 GHz can deliver up to 1 gigabit per second (Gbps).
  • 6 GHz can deliver up to 2 Gbps.
 
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  • #15
I see a factor of about 8 between 2.4 and 5.
"Up to" is anyway more likely marketing-speak than anything real.
 
  • #16
Yesterday was tiring. First thing in the morning, I found that the router is actually working on b/g mixed protocol rather than n on the 2.4 GHz band. And no matter how many times I tried to change it, it still returned to b/g mixed mode.

When the technician came to relocate the router, he told me that the company has fixed all routers to b/g mixed and does not allow the n mode. Nobody knows why. He said that the max. speed will be around 40 Mbps unless I use my own router. I do have a single band router, so I connected that to the ISP router via ethernet and switched off the 2.4 GHz band in the ISP router. Got a speed of 60 Mbps on 2.4 GHz and 110 Mbps on 5 GHz. I was happy.

An hour later, the 5 GHz band stopped giving anything higher than 20 Mbps. Fiddled with the settings, but no resolution. After a whole afternoon of splitting hairs, decided to factory reset the ISP router. And that resolved the issues, except one: as others have reported, the speed on the 2.4 GHz band, even after using a router that supports n protocol, is now unfortunately not rising above 30 Mbps. No idea why. Initially, it did give 60–70 Mbps. Now it's not. Probably I have to live with that.

Edit: Interestingly, if I do the speed test to the same servers from my laptop, I get a higher speed, typically > 80 Mbps, on the 2.4 GHz band. On mobile, I am not getting higher than 30 Mbps, though I do get 100 Mbps on the 5 GHz band.
 
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  • #17
Vanadium 50 said:
I just measured mine on that band only and get 29.
For comparison, what's the speed on the 5 GHz band?
 
  • #18
Wrichik Basu said:
or comparison, what's the speed on the 5 GHz band?
Gonna downvote that too?
Vanadium 50 said:
I see a factor of about 8 between 2.4 and 5.
 
  • #19
Vanadium 50 said:
Gonna downvote that too?
Downvote? What did I downvote? And how do you downvote anyway? This is not Stack Exchange.
 
  • #20
You said the post made you Sad. It's not our fault that that's how fast 2.4 GHz Wifi goes. It's really not.

As far as b/g vs/.n, if there is a single b/g device on the network, the whole network drops to b/g speeds. That's in the spec. From experience, if there is the tiniest bit of noise or interference, the system also drops to b/g.
 
  • #21
Vanadium 50 said:
You said the post made you Sad.
How's that equivalent to a downvote? And where did I say that you are at fault?
 
  • #22
This thread is wandering a bit, and its signal/noise ratio is dropping. OP -- are there any more questions about your original query that you still have?
 
  • #23
Wrichik Basu said:
even after using a router that supports n protocol
802.11n is ancient technology. Assuming it is possible to replace the router, 802.11ac should be affordable and have much greater throughput.
 
  • #24
pbuk said:
802.11n is ancient technology. Assuming it is possible to replace the router, 802.11ac should be affordable and have much greater throughput.
Yeah, I should have spent the money and bought a dual band router three years back. It's on my list. I should mention that the current ISP router supports both 11ac and 11a on the 5 GHz band, but again, they've forcefully fixed it to only 11a.
 
  • #25
Dual-band solves the problem, but it does so by using the 5 GHz band.

Originally, 2.4 GHz gave you a nominal 11 Mbps, and if you got 5 in real life you are doing well. Today, with layers of new standards and varying degrees of backward compatibility, practically one can do maybe 6x that. That's pretty good. To do better, you need a technology change - like to 5 GHz.

The number on the box is really mostly irrelevant. "Up to X Mbps" just means that they promise you won't get X+1.
 
  • #26
Odd that nobody asked what type of modem/router the OP was using. If, like most, it provides port(s) for wired LAN connection, the simple solution is to connect your own modern WiFi router there. You are then free to configure it whatever way you wish, irrespective of the ISP’s arbitrary bad choices for the rental modem/router.
 
  • #27
Wrichik Basu said:
The 5GHz band gives a speed of > 100 Mbps upload and download using speedtest.net, which is great. The 2.4 GHz band, however, gives only a speed of around 30 Mbps
That's consistent with what I get, typically, although I do not have any trouble (well, usually not any) with Skype sessions. I don't know if Zoom is worse that Skype for bandwidth but it could be.

EDIT: Wow ! All my neighbors must still be asleep. I got 350mhz download this morning on my 5G connection.
 
  • #28
The 2.4 GHz band is used by all the smart home devices in the world (the so-called Internet of Things), so the congestion may be on the ISP end even if you don't even have a smart thermostat in your house.
 

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