The Macworld Lab has a small collection of Thunderbolt peripherals , and we thought we should put them to cultivate to respond questions we had about connectivity and how devices affect public presentation .
After test dozens of scenarios , we found that — for the most part — the two useable bi - directing 10Gbps groove in the MacBook Pro ( Late 2011 ) were more than capable to keep up with the demand of multiple depot machine on a Thunderbolt daisy chain . However , if you add multiple displays to that chain , the throughput of some drives can be hard limited .
( For your reference : The iMac ( Mid 2011 ) uses the same Light Ridge Thunderbolt restrainer as the MacBook Pro , but the iMac has two Thunderbolt ports and put up up to four bi - directive , 10Gbps channels . The MacBook Air ( Mid 2011 ) uses an Eagle Peak Thunderbolt restrainer that provide for two bi - directing 10Gbps channel . )
Results are in MBps. Testing performed on a late 2011 17-inch 2.4GHz Core i7 MacBook Pro.—Macworld Lab testing by James Galbraith and Mauricio Grijalva
Drives in a daisy chain
The Thunderbolt drives involved in our examination were the PromisePegasus R6RAID array , the LaCieLittle Big Disk Thunderbolt Series SSD , and the LaCieLittle Big Disk Thunderbolt Series 2TBhard drive .
To get a set of baseline speeds to guess carrying into action , we sequester one parkway at a time , with no other devices , to a 17 - column inch 2.4GHz Core i7 MacBook Pro . We launch the AJA organization mental test several times — specifically , the 2 GB , 1920 - by-1080 , 10 - bit RGB tryout — and calculated average performance hurrying . The Pegasus R6 was the fastest machine we quiz , with a write speed of 538.1MBps and a read speed of 519.3MBps . The LaCie SSD post a write speed of 253.0MBps and a read speed of 480.5MBps . The LaCie operose movement clocked in with a write focal ratio of 184.7MBps and a read fastness of 203.1MBps .
We then impound all three depot devices to the MacBook Pro , with the Pegasus R6 first in the chain of mountains join directly to the MacBook Pro . The LaCie SSD was second in the Ernst Boris Chain , and the LaCie heavy drive was last . When we ran the AJA organisation screen again , the Pegasus R6 saw a svelte execution betterment , with a write stop number of 543.0MBps , and a read f number of 520.3MBps .
The LaCie SSD , second in the range of mountains ( attached to the Pegasus R6 ) , scored about the same as it did when connected alone , with a write speed of 246.9MBps and a read speed of 469.4MBps . The LaCie hard drive , the last equipment on the chain ( attached to the LaCie SSD ) , mail scores that were a speck quicker than when impound alone : a write fastness of 190.1MBps , and a read speed of 205.4MBps .
We then changed the order of the gimmick on the chemical chain , placing the Pegasus R6 last on the range of mountains , and the LaCie SSD first , with the LaCie hard drive in - between . The Pegasus R6 score were just a jot slower , with a write speed of 532.8MBps , and a read speed of 513.2MBps . With the LaCie SSD connected to the MacBook Pro , it scored about the same as it did in the second side . The same was true for the LaCie hard drive .
Results are in MBps . examination performed on a late 2011 17 - inch 2.4GHz Core i7 MacBook Pro.—Macworld Lab examination by James Galbraith and Mauricio Grijalva
Results are in MBps. Testing performed on a late 2011 17-inch 2.4GHz Core i7 MacBook Pro.—Macworld Lab testing by James Galbraith and Mauricio Grijalva
Drives and a display in a daisy chain
In our next serial of psychometric test , we added an Apple Thunderbolt Display to the oddment of the string . All of the crusade turn in speeding very alike to the upper they posted without the display . swop the Thunderbolt Display with an Apple 27 - in guide Cinema Display did n’t change performance much , either .
With the Thunderbolt Display as the first equipment ( and the only display ) in the chain , the LaCie SSD experienced a belittled performance strike . There was no literal execution alteration on the LaCie backbreaking drive .
Daisy chain with two external displays, three drives
Things got interesting when we connected two Thunderbolt Displays to the goal of the chain . Having multiple display in a chain affect carrying out . When we record our results , we face for other report to see if anyone else had noticed standardized demeanor , and we saw a report byAnandTech .
The LaCie SSD become from 249.7MBps ( write ) and 472MBps ( read ) with one Thunderbolt Display attached , to 153.9MBps ( write ) and 438.8MBps ( read ) with two Thunderbolt Displays on the chain . The LaCie hard drive ’s read performance was insensible , but the write speed decrease from 183.9MBps to 159.4MBps .
The Pegasus R6 saw the most dramatic change , with its write focal ratio dropping from 553.7MBps to 231.0MBps , and its read speed dropped from 527.4MBps to 420.7MBps .
Granted , a apparatus with a pair of two Thunderbolt Displays , a Pegasus R6 , a LaCie Little Big Disk SSD , and a LaCie Little Big Disk unvoiced drive is moderately expensive ( $ 8,593 from the Apple Store ) . And since most Thunderbolt computer peripheral available now tend to be for high - closing usage ( RAID arrays , video seizure boxes , etc . ) , the users involve in intricate Thunderbolt daisy chains tend to be professionals . But finally , as Thunderbolt peripherals proliferate and come down in Leontyne Price , even casual Mac user will belike be create chains of Thunderbolt - equipped devices
We also establish that frame one of the Thunderbolt Displays at the beginning of the range of mountains and putting the other Thunderbolt Display on the end did n’t affect the carrying into action of the Pegasus R6 , but this conformation did slow up down the write speed of the LaCie SSD from 153.9MBps to 139.3MBps , and the LaCie hard driving from 159.4MBps to 144.1MBps . understand speed was also a bit slower on the SSD in this chain , going from 438.8MBps to 412.8MBps .
With a Thunderbolt Display still at the offset of the chain , we swapped the Thunderbolt Display at the ending of the chain with a Cinema Display . The Pegasus R6 regained some of its swiftness , with a write speed of 433.4MBps and a read speed of 440.8MBps . The LaCie hard drive also benefitted , with speeds like to when there was just a unmarried Thunderbolt Display attached to the beginning of the Ernst Boris Chain . The LaCie SSD regained some background , with a write speed of 208.5MBps and a read speed of 427.8MBps .
Results are in MBps. Devices are listed in the order of placement in the daisy chain. Testing performed on a 2011 27-inch BTO iMac with a 3.4GHz Quad Core i7.—Macworld Lab testing by James Galbraith
resultant role are in MBps . Devices are heel in the order of placement in the daisy Sir Ernst Boris Chain . Testing do on a 2011 27 - in BTO iMac with a 3.4GHz Quad Core i7.—Macworld Lab examination by James Galbraith
iMac, two displays, three drives
To see if the MacBook Pro was a cistron in performance , we ran some tests using a build - to - order27 - inch 3.4GHz Core i7 iMac . We tested the Pegasus R6 by itself and saw a write speed of 533.9MBps and a read speed of 519.5MBps . With a Thunderbolt Display attached before the Pegasus R6 in the chain , we saw a write speed of 527.7MBps and a read upper of 526.8MBps . When we attached a Cinema Display to the Pegasus R6 ( with the Thunderbolt Display still at the beginning of the mountain range ) , the Pegasus R6 ’s write upper drop to 430.1MBps , and its read hurrying dropped to 432.8MBps . Placing the Pegasus R6 between two Thunderbolt Displays dropped the write speed to 231.6MBps , while read f number dipped , but at 396.9MBps , not by as much .
We also ran a few tests to see if the performance degradation would show up in everyday use . We copied a 6 GB filing cabinet from the iMac to the Pegasus R6 , parallel the file on the Pegasus R6 , and then copied the duplicate file back to the inner SSD on the iMac . We saw a Pegasus R6 write speed of 225MBps in two configurations : with just a undivided Thunderbolt Display attach to the array , and then with the Thunderbolt and Cinema Display attached . With two Thunderbolt display , the write velocity slowed down a chip to 214.3MBps . Duplicating the file on the Pegasus R6 shew bigger differences , with 299.0MBps with no display attached , 297.5MBps with a single Thunderbolt Display attached , 247.1MBps with a Thunderbolt Display and a Cinema Display attached , and just 163.8MBps with two Thunderbolt Displays tie . When reading the files back to the internal SSD , we saw less of a execution remainder , with speeds wander from 184.0MBps with no display attached to 178.0MBps with two Thunderbolt Displays connected .
The ground for the performance decrease in a two - presentation setup is two - fold . First , the Pegasus is dissipated and can put mass of bandwidth to use . secondly , each Thunderbolt Display gobbles up about 7Gbps of an outward channel ’s available 10Gbps bandwidth . Display traffic is one - fashion , so that ’s why the read bucket along from the Pegasus are n’t as affected . To essay this out , we bond the second Thunderbolt Display to the iMac ’s 2nd bolt interface and find performance to come back to the level of a setup with just one Thunderbolt Display bond .
Thunderbolt Software Update 1.1
During our testing , we found that the Pegasus R6 was fasterbeforeapplying theThunderbolt Software Update 1.1 . The single file transport tests we ran on the iMac were very close to the mental test runs with the update use , but our Indian file duplicate tests see speeds as tight as 341.7MBps without the update , versus a acme of 299.0MBps with the update .
Using the AJA System Test with the iMac , we saw a heyday publish speed of 644.3MBps and a peak take speed of 521.3MBps from the Pegasus R6 . Interestingly , if we re-start the Mac with the Pegasus R6 connected , but did not restart the regalia , write speeds would drop to about 559.9MBps . Read speeds were n’t affected much , with speeds average out 525.4MBps . Restarting the Pegasus R6 would bring the write speeding back up to the 644MBps range .
Once we installed Thunderbolt Software Update 1.1 , the mark stay on the same whether we restarted or not . The Pegasus R6 ’s write stop number of 534MBps , however , was a drop from the 644MBps we ensure before installing the update . The Pegasus R6 had a read speed of 520MBps . Neither of the LaCie drives were affected by the update .
One other thing we find oneself with the Pegasus R6 : If you desire to play audio through the built - in speakers on a Thunderbolt Display , seize the array to the display . Do n’t attach the exhibit to the Pegasus R6 — the audio play through the Thunderbolt Display ’s speaker would twist , stutter and turn back when running the AJA System Test on the Pegasus R6 . Audio playback was n’t affected when the display was ahead of the Pegasus in the range . With the LaCie drive , the sound recording played fine during the AJA tests , disregarding of the drive ’ position on the chain .
[ James Galbraith is Macworld ’s lab managing director . ]
