Thunderbolt 3 Ports on Right Side of 13-Inch MacBook Pro Have Reduced PCI Express Bandwidth

[MacRumors]

Apple has published a detailed support document highlighting the capabilities of the Thunderbolt 3 USB-C ports on the new MacBook Pro, unveiling some previously unknown details and outlining the different adapters that are needed to connect various accessories.

According to the document, while all of the ports on the 15-inch MacBook Pro and the 13-inch MacBook Pro without a Touch Bar offer full Thunderbolt 3 performance, only two of the four ports on the 13-inch MacBook Pro with a Touch Bar support Thunderbolt 3 at full performance.

The two ports on the right side of the machine have Thunderbolt 3 functionality but with reduced PCI Express bandwidth. For that reason, Apple recommends plugging higher-performance devices into the left-hand ports on that machine.

Late-2016 MacBook Pro models vary slightly in the data speeds they provide to each Thunderbolt 3 port.

MacBook Pro (15-inch, Late 2016) delivers full Thunderbolt 3 performance on all four ports.

MacBook Pro (13-inch, Late 2016, Four Thunderbolt 3 Ports) supports Thunderbolt 3 at full performance using the two left-hand ports. The two right-hand ports deliver Thunderbolt 3 functionality, but have reduced PCI Express bandwidth.

MacBook Pro (13-inch, Late 2016, Two Thunderbolt 3 Ports) delivers full Thunderbolt 3 performance on both ports.

As for USB, all of the USB-C ports on all MacBook Pro models offer USB 3.1 Gen 2 (10Gb/s) transfer speeds when connected to a USB accessory.

Other interesting tidbits in the document include the fact that six devices can be daisy-chained to each Thunderbolt 3 port on the MacBook Pro, and only one power supply can be used to charge the machine. You can attach multiple power supplies, but it's only going to draw power from the one that provides the most power.

Power supplies that exceed 100W have the potential to damage the Macbook Pro, and accessories like the USB-C VGA Multiport Adapter or the USB-C Digital AV Multiport Adapter can only provide up to 60W of power, which will offer slow or delayed charging in the 15-inch MacBook Pro. Apple recommends charging the 15-inch model with the power supply it ships with.

Apple also outlines powering attached devices with Thunderbolt 3 ports. The 15-inch MacBook Pro and the 13-inch MacBook Pro with Touch Bar can power two devices that use up to 15 watts and two additional devices that use up to 7.5 watts. The 13-inch MacBook Pro with no Touch Bar and two Thunderbolt 3 ports can power one device that uses up to 15 watts and one device that uses up to 7.5 watts.

If you're planning to purchase a new MacBook Pro and are confused about which adapters you're going to need so it will work with your existing equipment and accessories, Apple's support document is a good reference to check out.

Article Link: Thunderbolt 3 Ports on Right Side of 13-Inch MacBook Pro Have Reduced PCI Express Bandwidth

 

[volcomvenom]

Well that sucks!

 

[DanGoh]

Every article brings me bad news.

 

[ZacNicholson]

Apple really screwed people who wanted the 13in.

 

[Kobayagi]

- New MacBook Pro Has Better Keyboard Than 12-Inch MacBook, But It's Expensive and Lacking Ports
- New MacBook Pros Max Out at 16GB RAM Due to Battery Life Concerns
- Apple Says It's Out of the Standalone Display Business
- New MacBook Pros Don't Include Backlit Apple Logo or Power Extension Cable
- Thunderbolt 3 Ports on Right Side of 13-Inch MacBook Pro Have Reduced PCI Express Bandwidth
- Apple Continues to Sell Base Model 2015 MacBook Pros at Same Price Points (ty @Pentium)

When will the bad news stop?

 

[Lakailb87]

Wow this is very unlike Apple. I remember when they came out with USB 3 they boasted how they didn't have to label them blue because all ports had the same speed!

Just one more inclination this is Cooks Apple and not Jobs' Apple

 

[puma1552]

jesus, every story since yesterday has just been worse and worse (except the removable ssd story).

 

[DanTheAppleMan]

This release just keeps getting better and better.

 

[farewelwilliams]

the news keep getting worse and worse.

 

[Mascots]

People are going to be so upset

 

[garirry]

Wow. This ****ing company has gone THIS far huh.

I thought that the final save point for this MacBook Pro was that at least it's a powerful computer. But clearly, Apple went as far as to reduce the speed of certain ports to save some pennies. Unacceptable, Apple. A pro machine my ass.

 

[blackcrayon]

Well that sucks!

Not likely to affect anyone's usage I don't think. That's still a huge amount of bandwidth for a external ports on a small laptop- at minimum the slower ports are still thunderbolt 1 speeds considering they get full usb 3.1 gen 2.

 

[Bubba Satori]

That's as easy to understand as the good old days of SCSI.

 

[Iconoclysm]

Wow. This ****ing company has gone THIS far huh.

I thought that the final save point for this MacBook Pro was that at least it's a powerful computer. But clearly, Apple went as far as to reduce the speed of certain ports to save some pennies. Unacceptable, Apple. A pro machine my ass.

Why are you convinced this is related to saving money instead of saving space and efficiency?

 

[jayducharme]

Apple is becoming a company I barely recognize. What happened to their practice of delighting us with "magical" technology. It's now getting to a point where I'm thinking, "I wonder in how many ways this new product is going to disappoint me?"

 

[SSD-GUY]

Anyone know why this is? Could kaby lake fix this so that all 4 ports have thunderbolt 3?

 

[nagromme]

How many actually need that bandwidth on even ONE port much less 3 to 4? And are actually in the market for the 13" Pro right now? How many were truly planning to get the 13" and hook up 4 TB3 devices that need that bandwidth? How many pay zero attention to far more significant positives, from screen quality to giant trackpad?

 

[Appleaker]

Why don't they specify the bandwidth of the right side Thunderbolt ports?

To be honest, I don't mind if they're a bit slower but the lack of an SD card slot was a mistake.

 

[Eidorian]

I was expecting a block diagram of the PCIe lanes and not just text.

 

[garirry]

Why are you convinced this is related to saving money instead of saving space and efficiency?

Because for $2300, I'll be expecting a computer that is capable to distribute bandwidth equally to all four ports.

 

[post_toastie]

Seriously? This release is getting worse and worse. And of course they won't say just how 'reduced' the performance is. Been waiting months for this release instead of buying last year's version. I might just go with those.

 

[Internet Enzyme]

Every article brings me bad news.

It's absolutely ridiculous. Every other article is something negative about it

 

[blackcrayon]

Wow. This ****ing company has gone THIS far huh.

I thought that the final save point for this MacBook Pro was that at least it's a powerful computer. But clearly, Apple went as far as to reduce the speed of certain ports to save some pennies. Unacceptable, Apple. A pro machine my ass.

Heh, the whining is almost comical at this point. Of course I'll be called a McPologist!

This is nothing new anyway, the previous smaller MacBooks (Airs, etc) had reduced Thunderbolt functionality over the larger pros. The cylinder Mac Pro doesn't have Thunderbolt 2 on all 6 ports, it divides 3 TB buses among them. So, the 13" MacBook Pros probably only have 1 thunderbolt 3 bus instead of 2 on the 15", or some other lesser vs. greater combination (not sure how the TB 3 hardware support works). You should've been complaining about this for years as it's been that way since Thunderbolt was introduced on the smaller devices vs. the larger.

 

[zhenya]

Wow. This ****ing company has gone THIS far huh.

I thought that the final save point for this MacBook Pro was that at least it's a powerful computer. But clearly, Apple went as far as to reduce the speed of certain ports to save some pennies. Unacceptable, Apple. A pro machine my ass.

This has nothing to do with saving pennies but rather how many lanes of PCI-Express are available on the Intel processors each computer uses. I had been wondering how they were going to pull off 4 completely equal ports, but rather certain that being Apple they would, but even they can't make something from nothing.

I think that in practice this will affect relatively few people, but it's a bummer nonetheless.

 

[lucasrant]

Could someone explain what this means, please?