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costica1234

macrumors regular
Original poster
May 21, 2013
203
150
Hello everyone,

After many months of frustration trying to figure out why my 15 inch rMBP was experiencing very slow download speeds (despite being on the 100 Mbps fiber optic plan from Virgin), I think I finally managed to identify the culprit. When open, the PDF Expert app from Readdle is negatively affecting the download speed on my rMBP running OS X El Capitan (version 10.11.4 to be precise). It is rather unusual for such an app to cause so much trouble system-wide, but at least I am glad I managed to narrow down this very irritating problem which was driving me crazy past 2-3 months (I obviously blamed Virgin, the router, even OS X which is getting crappy these days, but apparently something completely different was at fault).

I put a video on YouTube demonstrating the issue:

.

Basically, I get the promised 100 Mbps download speed when PDF Expert is not running, otherwise it's ~10-15 Mbps (it has been even lower than this a couple of days ago when I ran the same test). Has anybody else experienced this abnormal behaviour with PDF Expert? I would kindly ask anyone having the app to run the same test I did and to report back with their results. I will be sending this feedback to Readdle support as well.

EDIT. I did reinstall the app in the meantime, but the same behaviour can be reproduced as in the video above.
 

Narcaz

macrumors 6502
Jul 18, 2013
419
558
That's a strange problem. No slowdowns with a 15'' rMBP late 2013/ 750m 10.11.4 / PDF Expert 1.4.1 MAS version/ 22mps download speed. I don't have flash installed, so i tried two different speedtest with safari. I also used Chrome on speedtest.net and i didn't notice any slowdown. I suspected PDF Expert for the occasional animation lag with OSX, but after using Preview again, they also appear (out of nowhere). I am waiting with my clean install for 10.11.5. According to Readdles twitter account, PDF Expert is also getting an update in the next few days.
 

costica1234

macrumors regular
Original poster
May 21, 2013
203
150
That's a strange problem. No slowdowns with a 15'' rMBP late 2013/ 750m 10.11.4 / PDF Expert 1.4.1 MAS version/ 22mps download speed. I don't have flash installed, so i tried two different speedtest with safari. I also used Chrome on speedtest.net and i didn't notice any slowdown. I suspected PDF Expert for the occasional animation lag with OSX, but after using Preview again, they also appear (out of nowhere). I am waiting with my clean install for 10.11.5. According to Readdles twitter account, PDF Expert is also getting an update in the next few days.

Thanks for your input. I did not mention in my original post, but I did a fresh install of 10.11.3 around February-March, since I had the same problem with slow internet connection. I thought that might have fixed it, but apparently not. I will be waiting for Readdle to reply with their feedback as well in the meantime. For me it is absolutely clear, whenever I open PDF Expert the internet connection becomes pretty much discontinuous and reaches very slow speeds once the app is brought alive. It is very annoying, but I cannot do anything about it at this moment. Might as well do a fresh install of 10.11.5 and hope that the issue will not manifest itself again.
 

Narcaz

macrumors 6502
Jul 18, 2013
419
558
Thanks for your input. I did not mention in my original post, but I did a fresh install of 10.11.3 around February-March, since I had the same problem with slow internet connection. I thought that might have fixed it, but apparently not. I will be waiting for Readdle to reply with their feedback as well in the meantime. For me it is absolutely clear, whenever I open PDF Expert the internet connection becomes pretty much discontinuous and reaches very slow speeds once the app is brought alive. It is very annoying, but I cannot do anything about it at this moment. Might as well do a fresh install of 10.11.5 and hope that the issue will not manifest itself again.

Have you checked the network connections from PDF Expert? You could use something like the Little Snitch Network Monitor and than block those. And is this related to a specific pdf file or does it happen with any pdf file?
 

costica1234

macrumors regular
Original poster
May 21, 2013
203
150
Have you checked the network connections from PDF Expert? You could use something like the Little Snitch Network Monitor and than block those. And is this related to a specific pdf file or does it happen with any pdf file?

Thanks for the suggestion, I will give that utility a try this evening. It happens with any PDF -- in fact it is just enough for the app to be open with zero PDFs and the issue arises immediately.
[doublepost=1463324502][/doublepost]UPDATE: I just tried the Little Snitch tool and there was only one connection that PDF Expert tried to make, which you can see in the attached picture. I denied that connection, but the speedtest was reporting slow download speeds just as before. Closed the app and everything went back to normal again...
Screen Shot 2016-05-15 at 15.50.22.png
 

Narcaz

macrumors 6502
Jul 18, 2013
419
558
Thanks for the suggestion, I will give that utility a try this evening. It happens with any PDF -- in fact it is just enough for the app to be open with zero PDFs and the issue arises immediately.
[doublepost=1463324502][/doublepost]UPDATE: I just tried the Little Snitch tool and there was only one connection that PDF Expert tried to make, which you can see in the attached picture. I denied that connection, but the speedtest was reporting slow download speeds just as before. Closed the app and everything went back to normal again... View attachment 631372

I'm sorry to hear that. Last chance try to deactivate hand off, because Readdles implementation seems a bit advanced: https://readdle.com/blog/2016/03/pd...devices-retweet-to-get-15-promo-codes-macios/
 
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costica1234

macrumors regular
Original poster
May 21, 2013
203
150
I'm sorry to hear that. Last chance try to deactivate hand off, because Readdles implementation seems a bit advanced: https://readdle.com/blog/2016/03/pd...devices-retweet-to-get-15-promo-codes-macios/
WOW, I have great news now :D. I disabled handoff from OS X system preferences (and from the PDF Expert's preferences pane as well, just in case) and now my internet connection is the same irrespective of the app being open or not! (download speed is within 60-80 Mbps in either case, but it is reasonable as my ISP might regulate traffic during evenings).

I have to say a big thank you for providing me with this tip! :) I will be reporting the situation to Readdle as well, just so that they are aware of this rather unusual issue, and potentially fix it in a future release. But thankfully, I can now cheer after a long and agonizing period of being completely puzzled as to why my rMBP was struggling so much with internet connection.
 

Narcaz

macrumors 6502
Jul 18, 2013
419
558
WOW, I have great news now :D. I disabled handoff from OS X system preferences (and from the PDF Expert's preferences pane as well, just in case) and now my internet connection is the same irrespective of the app being open or not! (download speed is within 60-80 Mbps in either case, but it is reasonable as my ISP might regulate traffic during evenings).

I have to say a big thank you for providing me with this tip! :) I will be reporting the situation to Readdle as well, just so that they are aware of this rather unusual issue, and potentially fix it in a future release. But thankfully, I can now cheer after a long and agonizing period of being completely puzzled as to why my rMBP was struggling so much with internet connection.

You're welcome.:)
 
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