I'm an idiot, I ran the test twice with the same flashed version.
Please accept my apologies for doubting, bbx10node.
Here are the actual results I get with a " 2 * HTTP_DOWNLOAD_UNIT_SIZE " setting:
2016-08-19 16:02:21 (195 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:02:24 (180 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:02:28 (238 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:02:29 (202 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:02:32 (193 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:02:40 (139 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:02:41 (248 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:02:44 (201 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:02:48 (237 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:02:52 (246 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:02:55 (202 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:00 (215 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:01 (249 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:04 (202 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:10 (184 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:11 (248 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:14 (201 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:18 (239 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:19 (293 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:22 (202 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:27 (238 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:27 (244 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:30 (200 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:39 (200 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:40 (251 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:43 (195 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:48 (220 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:03:49 (246 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:03:51 (200 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:03:57 (207 KB/s) - `test1MB.jpg' saved [1046750/1046750]
Holy crap, we're at about 10 times faster than with the standard version.
I ran it a second time because I could believe the results, but it's absolutely reproductible.
I tested with 3x but then wget complains that "Connection closed at byte 2920. Retrying." and never succeeds in downloading a single file.
I also tested with 1.5x (2190 bytes) but this leads to the slowest result of all:
2016-08-19 16:20:14 (18,8 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:20:42 (18,2 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:21:38 (18,1 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:21:44 (18,5 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:22:01 (30,5 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:22:57 (18,2 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:23:03 (18,1 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:23:32 (17,7 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:24:29 (18,2 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:24:34 (18,5 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:25:03 (17,6 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:26:00 (18,0 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:26:06 (18,6 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:26:34 (17,8 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:27:31 (18,2 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:27:36 (19,0 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:28:04 (18,1 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:29:01 (18,2 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:29:07 (16,1 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:29:35 (18,3 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:30:33 (17,9 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:30:39 (19,1 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:31:07 (18,2 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:31:46 (26,4 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:31:53 (24,8 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:32:21 (18,1 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:33:17 (18,6 KB/s) - `test1MB.jpg' saved [1046750/1046750]
2016-08-19 16:33:22 (19,1 KB/s) - `test100K.jpg' saved [98828/98828]
2016-08-19 16:33:51 (17,5 KB/s) - `test500K.jpg' saved [512705/512705]
2016-08-19 16:34:47 (18,5 KB/s) - `test1MB.jpg' saved [1046750/1046750]
My conclusion is that the "2x" setting bbx10node has found is not just a "sweet spot", like the top of a curve. It really seems to make the conditions "just right" to trigger extremely fast transfers compared to the default speed.
Now does someone have an idea why it is so ? And can it be made the default ?
I don't see any drawback to it (except its "black magic" side) and as I said all downloaded files have been successfully tested for correctness after download.
Kind regards,
Vicne