Why Are All USB WiFi Adapters Slow?

[Appletax]

Why is it that no USB WiFi adapters will allow me to use use the full speed of my Internet connection?

With my personal high-end gaming PC, I have tried a Belkin and a TP-Link WiFi-N adapter, as well as the integrated WiFi-AC MM.2 adapter card. None of them will let me use my Internet's full speed (60Mb/s); I get around ~20Mb/s). WiFi router is a TP-Link WiFi-N model that works perfectly with mobile devices. Issue occurs with Windows 8 and 10 and using the latest drivers doesn't help.

This issue also occurs for my step-grandparents who have a Netgear WiFi-N USB Adapter on Windows 7 and another model on a Windows 10 PC, both connected to a WiFi-N router. They're getting ~20Mb/s when they should be getting 60Mb/s.

So 5 different WiFi adapters on Windows 7, 8, 8.1 and 10 using different routers do not provide full-speed Internet.

Tablets, cell phones and laptops connected to these routers work perfectly fine and get full-speed Internet.

The only way to get full-speed Internet on these desktops is to use Ethernet cables.

What the heck is up with that? Do USB WiFi adapters just suck?

 

[YeOldeStonecat]

Ahh yes software NICs...depending so much on CPU cycles.

Back in the dial up days...."Winmodems" was the joke of connections.

 

[Appletax]

Ahh yes software NICs...depending so much on CPU cycles.

Back in the dial up days...."Winmodems" was the joke of connections.

Got a Core i7-4770K overclocked to 4.2GHz, so there's plenty of CPU cycles to go around

It's still a hardware NIC just like an Ethernet NIC...both are hardware devices connected to the mobo and both use software/drivers.

 

[YeOldeStonecat]

It's not "hardware" like a good integrated or PCI variant NIC...which are built into much faster buses on the motherboard. Good onboard or dedicated NICs have their own processor and supporting chipset.

USB..pretty much nothing...certainly no dedicated processor, and a wimpy radio and wimpier antenna to boot. And in addition to that...they use a USB bus...which is shared, heavily CPU dependent, and...a far cry from an onboard NIC that uses a direct bus on the motherboard. Take some peeks at actual sustained throughput of USB buses...not what theoretical speeds are.

Doesn't matter how hairy the nuts of your CPU you think you have...it's still "borrowed cycles" from the operating system...your network traffic has to stand in line with other things. Nothing beats proper dedicated hardware for peripherals....nothing! Just like RAID controllers. Just like modems. Just like sound cards. Just like graphics cards. so on...and so forth..

 

[Appletax]

It's not "hardware" like a good integrated or PCI variant NIC...which are built into much faster buses on the motherboard. Good onboard or dedicated NICs have their own processor and supporting chipset.

USB..pretty much nothing...certainly no dedicated processor, and a wimpy radio and wimpier antenna to boot. And in addition to that...they use a USB bus...which is shared, heavily CPU dependent, and...a far cry from an onboard NIC that uses a direct bus on the motherboard. Take some peeks at actual sustained throughput of USB buses...not what theoretical speeds are.

Doesn't matter how hairy the nuts of your CPU you think you have...it's still "borrowed cycles" from the operating system...your network traffic has to stand in line with other things. Nothing beats proper dedicated hardware for peripherals....nothing! Just like RAID controllers. Just like modems. Just like sound cards. Just like graphics cards. so on...and so forth..

Well said, but what about my MM.2 wireless AC card that is connected via the PCIe bus like an Ethernet NIC would be? That card should be super faster...should at least let me get 60Mb/s from my Internet. PCIe = direct connection to the South Bridge for each individual slot.

Even if the radio and antenna are wimpy, it shouldn't be that bad given that the router is only a few feet away.

It's like desktops just do not play well with wireless, period, unless the wireless is embedded, like you get with all-in-ones.

 

[NJW]

Even if the radio and antenna are wimpy, it shouldn't be that bad given that the router is only a few feet away.

There are 1001 things that could be interfering with any radio comms, no matter what the distance. Using Wi-Fi at a distance of 'a few feet' is a poor choice over Ethernet, imo.

Got a Core i7-4770K overclocked to 4.2GHz, so there's plenty of CPU cycles to go around

All that extra radiation ...

It's still a hardware NIC just like an Ethernet NIC...both are hardware devices connected to the mobo and both use software/drivers.

Just because they're both called 'driver' doesn't mean they achieve their respective function in the same way. Apples and oranges are both called 'fruit'.

 

[YeOldeStonecat]

Well said, but what about my MM.2 wireless AC card that is connected via the PCIe bus like an Ethernet NIC would be? That card should be super faster...should at least let me get 60Mb/s from my Internet. PCIe = direct connection to the South Bridge for each individual slot.

Even if the radio and antenna are wimpy, it shouldn't be that bad given that the router is only a few feet away.

It's like desktops just do not play well with wireless, period, unless the wireless is embedded, like you get with all-in-ones.

There's much more to wireless performance....of course USB versus an embeddeed, or PCI variant (mini PCI, PCIe, etc).
The particular wireless chipset is the next contributing factor. Much as with wired ethernet NICs...you have your Intels (best), Broadcoms, Atheros (yuck), Realtek (yuck), years ago 3COM was great.
I see plenty of mini PCI e NICs perform strong on desktops.

 

[Diggs]

As I remember from the actual tests by PC Magazine(?), WiFi delivers only a paltry fraction of what it is rated for. At the time of the testing a 54 mps router could only deliver less than 20 mps in perfect conditions, a 150 mps router struggled to achieve 50 mps, and those conditions deteriorated quickly with distance, other users, other routers on same channel, etc. They were analyzing popular consumer gear at the time, not commercial stuff.

 

[Markverhyden]

First place you will NEVER get your provisioned bandwidth 100% of the time. Depending on the provider and the destination path it is completely normal to get 20-50% of the provisioned speed. Even less. And I'm talking hardwired to an ISP's modem. As you add extra layers on your end it just gets worse. Especially when you add a USB WiFi adapter. When I compare the difference between a USB and Thunderbolt on my retina it's like night and day. USB is much slower on average.

 

[brandonkick]

My comcast cable internet is usually 150+ Mbps wired.... but I can get well over 50 Mbps with
a Rosewill usb adapter that I paid $10 for a few years back. I liked them so much I bought a
few because they worked with everything right out of the box. Back at that time they worked
out of the box with the latest version of OSX and they worked with linux machines very easily.

It is a bit strange though, almost like there is an "overhead" for the wireless transmission. I remember
when my comcast cable was closer to 50Mbps.... my wireless topped out in the 30's somewhere.

I guess what I can contribute here is that no... not all USB adapters suck. No USB adapter is as good
as an ethernet cable IMO, but they all do not suck. If I couldn't go hard wired, I'd be content with
my wireless. You can always upgrade to a good PCI-E solution.