How much processing power does the Ethernet shield/library take?

If I attach an Ethernet shield to an Arduino UNO and then use the Ethernet library in a sketch, how much of the processing power of the microcontroller will be taken up by the Ethernet library?

I ask because I'm guessing it takes up a pretty significant portion of the processing power, but am not sure as I've never used Ethernet before.

Thanks!

I ask because I’m guessing it takes up a pretty significant portion of the processing power, but am not sure as I’ve never used Ethernet before.

You’d be wrong, then. The processing is done by the Ethernet shield. All the Arduino does is read and write data from/to the shield via the SPI pins.

PaulS:

I ask because I'm guessing it takes up a pretty significant portion of the processing power, but am not sure as I've never used Ethernet before.

You'd be wrong, then. The processing is done by the Ethernet shield. All the Arduino does is read and write data from/to the shield via the SPI pins.

This is one time I'm glad to be wrong, then!

Thanks :)

This is one time I'm glad to be wrong, then!

There is a HUGE difference between processing power and the time that is involved in doing the processing.

There isn't much that the Arduino does in processing client or server data, but it still takes a lot of time to do it.

Perhaps your question wasn't really about power, but was more about time, so your relief may be unwarranted.

I agree with PaulS. It is a matter of time. The SPI bus is the holdup. Since your username is RoboticsGuy, I presume you are using the ethernet for robotics control. I do too. I prefer UDP for that. I get about 10 packets/second reliably. If you need more than that, I recommend going with another device, like a Raspberry Pi (less I/O but easy to get) or a BeagleBone Black (more I/O but hard to get).

For non-trivial tasks in combination with Ethernet communication I often hit the UNO memory limitations soon. Maybe you should consider using a Mega.