external usb 3g modem vs built in 3g

[josefn]

Is there any difference in terms of energy consumption when using a tablet with internal 3g internet and one without such feature through external 3g dongle? When using a dongle on the laptop for example I noticed it is heating moderately, so there must be much energy wasted in it. How about a built in 3g, is it the same story or does it operate more efficiently?

 

[mikedt]

I'd hazard a guess, and say they'd be similar. They're both a 3G radio and modem, it's just how they're connected is different. USB 3G/4G modems can run a bit warm, but in a tablet any heat generated by the modem is going to be absorbed by quite a large device in comparison to a small USB dongle. Modern USB cellular modems are a lot more efficient than they used to be. The first Huawei ones, like the e220, could run very warm and sometimes required two USB ports to power them from a laptop, using a "Y" cable. I've sometimes used a modern Huawei, EC122 CDMA/EV-DO USB dongle modem, and that barely gets warm at all, and doesn't require a "Y" cable.