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View Full Version : Can the new MacBook Air power a 2nd external display via USB power




jussha
Aug 4, 2013, 02:03 PM
Hey everyone, so I got the new macbook air and on the apple site it says that the new air is only capable of powering 1 external display at a 2560 x 1440 resolution via its thunderbolt port. Now I've been able to successfully use the displaypad app to get my ipad to act as a 2nd display, but I was wondering if anyone knew if I could also use a USB powered display, such as this AOC monitor, rather than my iPad as the 2nd external display. Anyone ever try this? Thanks!

http://www.amazon.ca/AOC-E1649FWU-16-Inch-Portable-Monitor/dp/B005SEZR0G/ref=sr_1_1?ie=UTF8&qid=1375642555&sr=8-1&keywords=aoc+usb+monitor



JimWPVB
Aug 4, 2013, 03:10 PM
The AOC 21(or 22) inch works fine via USB - no power brick needed. My use was primarily for work, which includes a lot of word processing and spreadsheets. It works well, after finding and downloading the correct drivers. There is a little lag, but not much and not troublesome. AOC has come out with a new 16 inch USB 3, which may eliminate the lag should it bother you.

DisplacedMic
Aug 4, 2013, 05:41 PM
Hey everyone, so I got the new macbook air and on the apple site it says that the new air is only capable of powering 1 external display at a 2560 x 1440 resolution via its thunderbolt port. Now I've been able to successfully use the displaypad app to get my ipad to act as a 2nd display, but I was wondering if anyone knew if I could also use a USB powered display, such as this AOC monitor, rather than my iPad as the 2nd external display. Anyone ever try this? Thanks!

http://www.amazon.ca/AOC-E1649FWU-16-Inch-Portable-Monitor/dp/B005SEZR0G/ref=sr_1_1?ie=UTF8&qid=1375642555&sr=8-1&keywords=aoc+usb+monitor

you can power two thunderbolt displays but short of a wireless option i'm not aware of another way to power 2 monitors.

edit: it appears i am mistaken. check out this thread:
http://forums.macrumors.com/showthread.php?t=1597826

scaredpoet
Aug 4, 2013, 11:51 PM
you can power two thunderbolt displays but short of a wireless option i'm not aware of another way to power 2 monitors.



It sounds like two different things here are meant by "powered."

No MacBook Air (nor any Macbook model for that matter) can supply enough power to a Thunderbolt display such that doesn't need to be plugged into a wall outlet, let alone can it do that for two Thunderbolt displays. In fact, it's usually the other way around: you plug the Thunderbolt display to the AC power, and it has a magsafe adapter to power the Mac Laptop.

What the MBA CAN do is drive two Thunderbolt displays however (meaning: have sufficient GPU capability to display video on both at their native resolution).



The AOC display, on the other hand, can be "powered" in the sense that it can run off USB power, without having to be plugged into a wall outlet. It can also drive that same display through the USB connection... though in general, USB-driven displays tend to be laggy and sub-par to even one with a VGA connection.

jussha
Aug 5, 2013, 07:29 PM
thanks for the help guys, I guess what I meant more along the lines is what scaredpoet is referring to, in whether the macbook air can drive 2 external displays in addition to its own display. I do think based on the one link saying it can drive 2 external thunderbolt displays that it should be able to also do a 2nd display if using a USB powered one instead. AOC does have a new USB 3.0 display coming out soon so maybe that will nullify some of the lag issues if using USB as the other source.

AXs
Aug 6, 2013, 01:33 AM
From what I read on another site, haswell is supposed to be able to support 2 screens. But unfortunately Apple didn't put thunderbolt 2 on their Air... so it still really limits to 1 external display.

Maybe usb-display will get improvements...

iAppl3Fan
Aug 6, 2013, 01:39 AM
It sounds like two different things here are meant by "powered."

No MacBook Air (nor any Macbook model for that matter) can supply enough power to a Thunderbolt display such that doesn't need to be plugged into a wall outlet, let alone can it do that for two Thunderbolt displays. In fact, it's usually the other way around: you plug the Thunderbolt display to the AC power, and it has a magsafe adapter to power the Mac Laptop.

What the MBA CAN do is drive two Thunderbolt displays however (meaning: have sufficient GPU capability to display video on both at their native resolution).



The AOC display, on the other hand, can be "powered" in the sense that it can run off USB power, without having to be plugged into a wall outlet. It can also drive that same display through the USB connection... though in general, USB-driven displays tend to be laggy and sub-par to even one with a VGA connection.

Great post. I couldn't put it better myself.

DisplacedMic
Aug 6, 2013, 02:25 AM
It sounds like two different things here are meant by "powered."

No MacBook Air (nor any Macbook model for that matter) can supply enough power to a Thunderbolt display such that doesn't need to be plugged into a wall outlet, let alone can it do that for two Thunderbolt displays. In fact, it's usually the other way around: you plug the Thunderbolt display to the AC power, and it has a magsafe adapter to power the Mac Laptop.

What the MBA CAN do is drive two Thunderbolt displays however (meaning: have sufficient GPU capability to display video on both at their native resolution).



The AOC display, on the other hand, can be "powered" in the sense that it can run off USB power, without having to be plugged into a wall outlet. It can also drive that same display through the USB connection... though in general, USB-driven displays tend to be laggy and sub-par to even one with a VGA connection.

yes, sorry - powered was obviously the wrong word. it is my understanding that the MBA can drive 2 TBDs as you daisy chain the second TBD to the first which is connected to the MBA via the thunderbolt port.

that is really interesting about the USB-powered display. i didn't know that!

----------

From what I read on another site, haswell is supposed to be able to support 2 screens. But unfortunately Apple didn't put thunderbolt 2 on their Air... so it still really limits to 1 external display.

Maybe usb-display will get improvements...

unless of course that second display is also a TBD which you can connect to the first.

jussha
Aug 6, 2013, 08:53 PM
based on this it does seem you should be able to drive 2 displays simultaneously using the thunderbolt port and the USB port to a USB powered monitor with the macbook air

http://9to5mac.com/2012/05/29/review-aoc-1080p-22-inch-displaylink-usb-powered-portable-monitor/

I think I'll wait til a USB 3 version of this 22 inch 1080P monitor comes out and see how well the new air can drive this monitor at the same time as my 23" ASUS IPS

jussha
Aug 12, 2013, 07:58 PM
so I finally got my AOC 22 inch USB monitor and it does work in addition to the ASUS PB238 IPS display I'm running off my display port/thunderbolt connection. I even am using the displaypad app with my first gen iPad to have 4 screens running in total with my macbook air (air screen, ASUS displayport, AOC USB, and iPad Wifi). It's pretty sweet and convenient having all this space now lol