Why avoid USB NIC?

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Just1Mohr
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Joined: Fri Jul 21, 2017 2:07 pm
Location: MN, USA

Why avoid USB NIC?

Post by Just1Mohr »

Recently I spent over a week researching my new network solutions: router & NIC.

That entire time I only ever found statements along the lines of "It technically doesn't matter. They perform equally." regarding PCI vs USB NICs.

Now that I've discovered this wonderful forum through this article, I'm much more concerned.


Does anyone have any evidence or facts to prove why USB NICs should be avoided as the article claims?
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Philip
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Post by Philip »

The USB interface works by "polling" interrupts, instead of generating them. The drivers create a "virtual" software network adapter that polls the USB interface periodically. Cheap USB dongles do a lot of processing/polling in that driver software, introducing noticeable issues, especially if the throughput is higher, or the CPU is fully utilized. The interface also has some speed limitations, especially USB 2.0 ports.
All that causes increased latency, decreased throughput, and possible periodic disconnects.

It should not be noticeable with newer USB 3 ports, better USB NICs, and faster computers that are not CPU-bound. However, it is not the best interface for gaming, where latency and throughput are important, and the computer is under load.

If you are using a newer laptop, your only options for wired Ethernet will go through USB these days, so newer drivers are generally better.

I hope this helps
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