Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

AirDrop is very slow!

tmanto02

tmanto02

macrumors 65816
Original poster
Jun 5, 2011
1,223
468
Australia
I tried out airdrop for the first time tonight and can I say that I was very disappointed. I transferred a 2 min video from my iPhone 5 to my girlfriends and it took almost 2 mins to transfer!

I assumed it would be almost as fast as airdrop for mac.

I think I will stick to instashare from now on.
 
It's supposed to start the transfer on Bluetooth and then move to WiFi as that is established between the two devices. I've noticed it seems a bit slow as well, as if the move over to WiFi on larger transfers is not happening. I haven't really done much research so far because I figured it would be fixed soon. I'll do some digging to see what I can find.
 
odin said:
It's supposed to start the transfer on Bluetooth and then move to WiFi as that is established between the two devices. I've noticed it seems a bit slow as well, as if the move over to WiFi on larger transfers is not happening. I haven't really done much research so far because I figured it would be fixed soon. I'll do some digging to see what I can find.
Click to expand...

Yeah I noticed that neither phones displayed the wifi symbol, so I was a bit thrown off by that, perhaps it transferred using Bluetooth instead of wifi like it is meant too.
 
A 2 minute HD video can be upwards to 300MB. Even at a 50Mbps internet connection it will take about 45 seconds.

I've only used it for pictures and for me at least its been pretty much instantaneous.

Isn't peer-to-peer slower than an internet connection though? So that would explain why it is slower than Mac Airdrop because that is done over a WiFi internet connection. I could be wrong, but thats what I've always thought.
 
AirDrop is very slow!

Mlrollin91 said:
A 2 minute HD video can be upwards to 300MB. Even at a 50Mbps internet connection it will take about 45 seconds.

I've only used it for pictures and for me at least its been pretty much instantaneous.

Isn't peer-to-peer slower than an internet connection though? So that would explain why it is slower than Mac Airdrop because that is done over a WiFi internet connection. I could be wrong, but thats what I've always thought.
Click to expand...

No, peer to peer is much, much faster. They can theoretically make use of whatever the fastest speed is for the latest wifi technology supported.

Wifi direct doesn't use the internet; it just communicates directly from device to device using wifi.

So around 300mbps for 802.11n I believe.
 
matttye said:
No, peer to peer is much, much faster. They can theoretically make use of whatever the fastest speed is for the latest wifi technology supported.

Wifi direct doesn't use the internet; it just communicates directly from device to device using wifi.

So around 300mbps for 802.11n I believe.
Click to expand...

The iPhone 5 maxes out at 150 Mbps on the 5 GHz band for battery saving purposes, so no 300 Mbps here, no sir.

(The MBP goes to 450 Mbps though.)
 
hafr said:
The iPhone 5 maxes out at 150 Mbps on the 5 GHz band for battery saving purposes, so no 300 Mbps here, no sir.

(The MBP goes to 450 Mbps though.)
Click to expand...

Ok so lets say that my video is 200MB. If the iphone's wireless chip is 150Mbps then airdrop should take around about 10 seconds not a couple of minutes.
 
tmanto02 said:
Ok so lets say that my video is 200MB. If the iphone's wireless chip is 150Mbps then airdrop should take around about 10 seconds not a couple of minutes.
Click to expand...

150 Mbps is a theoretical max for the 5 GHz bands, you won't reach those speeds in real life transfers.

Using 2.4 GHz instead of 5 GHz, only one stream, encrypting... These things all mean slower transfer speeds, by quite a lot actually. But I'm in no way, shape or form an expert when it comes to wireless transmissions, nor do I know how AirDrop actually works (more than using an ad hoc wifi peer to peer connection) But I wouldn't be surprised to see speeds at something like 10 Mbps, which would be about three minutes for a 200 MB movie clip...
 
tmanto02 said:
Ok so lets say that my video is 200MB. If the iphone's wireless chip is 150Mbps then airdrop should take around about 10 seconds not a couple of minutes.
Click to expand...

Those rated Wifi speeds are always very very theoretical. For example 54mbit wifi mostly maxes out at around 20-25mbps. But I guess 75-100mbps should be doable if the devices are close to each other and connect peer to peer.
 
tmanto02 said:
Ok so lets say that my video is 200MB. If the iphone's wireless chip is 150Mbps then airdrop should take around about 10 seconds not a couple of minutes.
Click to expand...

150 Mbps rated at the lowest physical link layer, and after protocol overhead up at the application link layer is around 90mbps at best.

90mbps = 10.72 MB/s

200MB / 10.72MB = 19 seconds.

I started out to clarify your numbers. But that's about right. I would certainly expect much quicker than 2 minutes.

There's a chance it's only negogiating over 2.4ghz. Which would roughly half those numbers 65or72mbps vs. 150. But should still transfer in under a minute.

In conclusion, I don't know.

It uses BT to negotiate, but WIFI to transfer. 2 min is still faster than bluetooth which is around a miserable 3mbps IIRC.

----------

A little wiki

Version 3.0 + HS of the Bluetooth Core Specification[36] was adopted by the Bluetooth SIG on 21 April 2009. Bluetooth 3.0+HS provides theoretical data transfer speeds of up to 24 Mbit/s, though not over the Bluetooth link itself. Instead, the Bluetooth link is used for negotiation and establishment, and the high data rate traffic is carried over a collocated 802.11 link.
Click to expand...
http://en.wikipedia.org/wiki/Bluetooth#Bluetooth_v3.0_.2B_HS

This moved forward into BT4.0 spec as well.

24Mbps, dropped to 14.4 mbps by an overhead guess (I do a .6 factor for wireless tech, .8 for wired). Which is 1.72MB/s.

200MB / 1.72 = 117 seconds.

There's your potential 2 minutes for a 200MB movie.

----------

more

Bluetooth 4.0 + HS supports data transfer speeds of up to 24 Mbps, whereby the Bluetooth link is used for negotiation and pair establishment and the high data rate traffic is carried over a co-located 802.11g link (the '+HS' portion).
Click to expand...

http://www.telecompaper.com/news/qualcomm-atheros-unveils-bluetooth-40-hs-chip-system--824090

Granted. iPhone uses Broadcom IIRC, it's going to be a similar spec since standards based.
 
hafr said:
150 Mbps is a theoretical max for the 5 GHz bands, you won't reach those speeds in real life transfers.

Using 2.4 GHz instead of 5 GHz, only one stream, encrypting... These things all mean slower transfer speeds, by quite a lot actually. But I'm in no way, shape or form an expert when it comes to wireless transmissions, nor do I know how AirDrop actually works (more than using an ad hoc wifi peer to peer connection) But I wouldn't be surprised to see speeds at something like 10 Mbps, which would be about three minutes for a 200 MB movie clip...
Click to expand...

Yeah I suppose there is a lot more to it than just "sending" the file.

Anyway I still think I will stick with Instashare, it lets you wirelessly transfer files to your mac too. :)
 
If I get a chance this week I'll try to do some relatively controlled transfers. Regardless of normal overhead and other issues, in my experience it seems a bit more sluggish than it should with larger transfers.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back