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wmy5

macrumors 6502
Original poster
Oct 27, 2012
328
51
upstate NY
Apple has started to sell the 2m Thunderbolt 3 cable:

https://www.apple.com/shop/product/MWP32AM/A/thunderbolt-3-pro-cable-2-m

As far as I know, any 40Gbps cable longer than 0.5m needs to be an active cable, and all active cable so far only compatible with USB 2.0 speed (480Mbps) when use with non-Thunderbolt USB-C devices. For example:


Apple claims that "this 2-meter cable supports Thunderbolt 3 data transfer up to 40Gb/s, USB 3.1 Gen 2 data transfer up to 10Gb/s, DisplayPort video output (HBR3), and charging up to 100W." I am very interested in how Apple has achieved this. Does anyone have some ideas?
 

BeatCrazy

macrumors 601
Jul 20, 2011
4,876
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Could you provide a source for this claim?
I guess Apple? https://www.apple.com/shop/product/MWP32AM/A/thunderbolt-3-pro-cable-2-m

It's the only TB cable on the market that is >.8m (i.e. it's active), yet still supports USB 3.1 Gen 2 data transfer at 10Gb/s and DisplayPort Alt mode.

Per CalDigit, this should not technically be possible. Some Apple is doing some kind of voodoo.
NOTE: Active cables do not support USB-C 3.2 Gen1 5Gbps, USB-C 3.2 Gen2 10Gpbs, USB3.0 & USB3.1. Only USB2.0.


EDIT - bit of a breakthrough here!

Recently I ordered the Cable Matters TB4 certified cable 2m via Amazon. It came yesterday but I hadn't even opened it up. Based on this discussion, I was curious as to if this "new" cable somehow got around the old limitations of 2m TB3 cables.

Well, it does!

You can see in the picture below my 2017 12" Retina MacBook. This is obviously USB 3.1 gen 1, only. I attached the TB4 cable to my ACASIS TB3 dock (includes the Titan Ridge TB3 controller for USB-C backwards capability), which has a 1TB WD Black SN750 inside. This combo has previously given me max speeds on my M1 Mac mini, see speed tests
here.

As you can see in my picture below, this new TB4 "active" cable supports at least USB 3.1 gen 1 at 5Gbps. The only device I have (I think) with USB 3.1 gen 2 is a 2020 12" iPad Pro. But I'm not sure if there is an iOS app to measure the speed of external drives?
IMG_0292.jpg
 
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wmy5

macrumors 6502
Original poster
Oct 27, 2012
328
51
upstate NY
I guess Apple? https://www.apple.com/shop/product/MWP32AM/A/thunderbolt-3-pro-cable-2-m

It's the only TB cable on the market that is >.8m (i.e. it's active), yet still supports USB 3.1 Gen 2 data transfer at 10Gb/s and DisplayPort Alt mode.

Per CalDigit, this should not technically be possible. Some Apple is doing some kind of voodoo.



EDIT - bit of a breakthrough here!

Recently I ordered the Cable Matters TB4 certified cable 2m via Amazon. It came yesterday but I hadn't even opened it up. Based on this discussion, I was curious as to if this "new" cable somehow got around the old limitations of 2m TB3 cables.

Well, it does!

You can see in the picture below my 2017 12" Retina MacBook. This is obviously USB 3.1 gen 1, only. I attached the TB4 cable to my ACASIS TB3 dock (includes the Titan Ridge TB3 controller for USB-C backwards capability), which has a 1TB WD Black SN750 inside. This combo has previously given me max speeds on my M1 Mac mini, see speed tests
here.

As you can see in my picture below, this new TB4 "active" cable supports at least USB 3.1 gen 1 at 5Gbps. The only device I have (I think) with USB 3.1 gen 2 is a 2020 12" iPad Pro. But I'm not sure if there is an iOS app to measure the speed of external drives?
View attachment 1729561

Thanks for the detailed report! I think both your TB4 cable and Apple's TB3 pro cable use upgraded active chips that support both USB 3.2 and TB3. The chips used in CalDigit cables are older versions, and only support USB 2.0.
 

BeatCrazy

macrumors 601
Jul 20, 2011
4,876
4,023
Thanks for the detailed report! I think both your TB4 cable and Apple's TB3 pro cable use upgraded active chips that support both USB 3.2 and TB3. The chips used in CalDigit cables are older versions, and only support USB 2.0.
Right, but until this new Cable Matters TB4 cable, no other >.8m cables on the market had this functionality, save for the Apple Pro TB3 cable. I also tested the Cable Matters TB4 cable with my iPad Pro 12" 2020. I couldn't find an app to measure speed, but it seem to connect to external drives and transfer at relatively fast speeds.

Maybe this functionality is part of the TB4 certification?

Seems like the Apple TB3 Pro cable is really a TB4 cable!
TB4.png
 

jimthing

macrumors 68000
Apr 6, 2011
1,970
1,123
Right, but until this new Cable Matters TB4 cable, no other >.8m cables on the market had this functionality, save for the Apple Pro TB3 cable. I also tested the Cable Matters TB4 cable with my iPad Pro 12" 2020. I couldn't find an app to measure speed, but it seem to connect to external drives and transfer at relatively fast speeds.

Maybe this functionality is part of the TB4 certification?

Seems like the Apple TB3 Pro cable is really a TB4 cable!
View attachment 1729623
As per the my post with you on the other thread, Apple's cable may be only DP 1.3, as I don't think it does 8K displays which need DP 1.4 that's in TB4 (active) cables?

BTW, you can use Speedtest with externals too. ;-)
 
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BeatCrazy

macrumors 601
Jul 20, 2011
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As per the my post with you on the other thread, Apple's cable may be only DP 1.3, as I don't think it does 8K displays which need DP 1.4 that's in TB4 (active) cables?
The Apple Pro TB3 2m cable does support HB3 DisplayPort Alt mode, which is included in the DP1.4 spec.
 

BeatCrazy

macrumors 601
Jul 20, 2011
4,876
4,023
As per the my post with you on the other thread, Apple's cable may be only DP 1.3, as I don't think it does 8K displays which need DP 1.4 that's in TB4 (active) cables?

BTW, you can use Speedtest with externals too. ;-)
Ya I know about using Speedtest with externals (you can see from my pics), but I don't know how to measure external drive speeds connected to an iOS device. My two iPad Pros are my only non-TB3 devices which support USB 3.1 gen 2.
 

jimthing

macrumors 68000
Apr 6, 2011
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The Apple Pro TB3 2m cable does support HB3 DisplayPort Alt mode, which is included in the DP1.4 spec.
But does Apple's cable support 8K 60Hz displays? They don't clarify, so if we presume that if they omitted to mention anywhere that their cable can do 8K 60Hz, it's likely it's only DP 1.3 (which also does HBR3):
https://en.wikipedia.org/wiki/DisplayPort#1.3

Ya I know about using Speedtest with externals (you can see from my pics), but I don't know how to measure external drive speeds connected to an iOS device. My two iPad Pros are my only non-TB3 devices which support USB 3.1 gen 2.
Ah, I see.
 
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BeatCrazy

macrumors 601
Jul 20, 2011
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But does Apple's cable support 8K displays? They don't clarify, so if we presume that if they omitted to mention anywhere that their cable can do 8K, it's likely it's only DP 1.3 (which also does HBR3):
https://en.wikipedia.org/wiki/DisplayPort#1.3


Ah, I see.
In my experience, Apple won't reference things (8K displays) that they don't sell :)

Since TB3 only supports DP1.2 (i.e. no HBR3), it would make more logical sense for the cable to support DP1.4 because there is no TB standard with "just" DP 1.3. It's either DP 1.2 or DP 1.4.
 

jimthing

macrumors 68000
Apr 6, 2011
1,970
1,123
In my experience, Apple won't reference things (8K displays) that they don't sell :)

Since TB3 only supports DP1.2 (i.e. no HBR3), it would make more logical sense for the cable to support DP1.4.
Doesn't that make it a TB4 cable then?

(it's like putting a jigsaw of info from various sources together, trying to get to the bottom with TB3/4 variants, lol!)
 
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BeatCrazy

macrumors 601
Jul 20, 2011
4,876
4,023
Doesn't that make it a TB4 cable then?

(it's like putting a jigsaw of info from various sources together, trying to get to the bottom with TB3/4 variants, lol!)
Yes, that's why I think the Apple TB3 Pro cable is indeed TB4 :)
 
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