Resolved What exactly does the T2 chip do for the machine?

revmacian

macrumors 68000
Original poster
Oct 20, 2018
1,658
1,351
USA
I own a MacBook Air (stock 2019, 8GB RAM, 128GB SSD) running macOS Catalina. Among the apps I use regularly are Calendar, Mail, Notes, Reminders, Safari, Numbers, Pages, Affinity Designer, Affinity Photo, GIMP and iMovie. I do see some dropped frames in iMovie. But I never see any beach balling, freezes or crashes in any app.

Is the T2 chip basically a second CPU? Is it like a math coprocessor? How many cores? If not, how can a 1.6GHz dual-core 8th-generation Intel Core i5 processor perform as well as it does? I always assumed less than 2.0 GHz meant "slow and incapable". I thought when I bought this machine, that it wouldn't perform as well as my 2017 base model MacBook Pro (non-Touch Bar) but it seems to be identical.

How is this possible on a MacBook Air? Is the T2 chip making that large of a difference here?
 

Fravin

macrumors 6502
Mar 8, 2017
250
126
Rio de Janeiro, Brazil
Thank you. I've seen that information but it doesn't explain how a MBA can perform so well..
That's because the way Mac OS is written.

Apple have been mastering matching OS and CPUs since Steve Jobs introduced the G3. Nowadays OS is written to squeeze CPU power and to increase performance. Even the fan less Macbook 12" can handle such workload with ease.

Windows is a complex mess. It has so many unnecessary processes running in background that I believe that no one can actually list their rules for the system.

BTW, T2 chips works like the NorthBridges in pre-Core era. Do you remember the Pentium days? There was a chip (named chipset) that handled the USB traffic, the PCI devices and all the other I/O ports. With the Core series, Intel added this tasks inside the CPU cores. So the CPU handles almost every traffic.

Apple has introduced T2 chips after Intel faced a few security flaws. The T2 chip, now, is responsible for the traffic between I/O ports (USB, TB, Keyboard, Disks) and CPU. It can handle Audio too. In MBP 16" the T2 chip are the main driver for audio.

As it is pretty beefy it can handle a lot of work with no heating, you can check iFix it pictures, it doesn't has any sort of heat dissipation solution.

Apple doesn't says too much about it, in technical terms. We don't know how fast it is and how to benchmark it.

But for sure it handles processes that once were CPU based.


Enjoy your MBA!
 

revmacian

macrumors 68000
Original poster
Oct 20, 2018
1,658
1,351
USA
That's because the way Mac OS is written.

Apple have been mastering matching OS and CPUs since Steve Jobs introduced the G3. Nowadays OS is written to squeeze CPU power and to increase performance. Even the fan less Macbook 12" can handle such workload with ease.
So, controlling the hardware as well as the software is indeed beneficial.


Windows is a complex mess. It has so many unnecessary processes running in background that I believe that no one can actually list their rules for the system.
That was exactly why I moved to Linux and BSD back in 2001.


BTW, T2 chips works like the NorthBridges in pre-Core era. Do you remember the Pentium days? There was a chip (named chipset) that handled the USB traffic, the PCI devices and all the other I/O ports. With the Core series, Intel added this tasks inside the CPU cores. So the CPU handles almost every traffic.

Apple has introduced T2 chips after Intel faced a few security flaws. The T2 chip, now, is responsible for the traffic between I/O ports (USB, TB, Keyboard, Disks) and CPU. It can handle Audio too. In MBP 16" the T2 chip are the main driver for audio.

As it is pretty beefy it can handle a lot of work with no heating, you can check iFix it pictures, it doesn't has any sort of heat dissipation solution.
Yes, I do remember the NorthBridge.. I spent years building desktop computers before moving to Apple machines in 2014. So, the T2 actually aids in the job that was performed by the NorthBridge chip? I wonder if this tie-in is why the T2 runs a system called BridgeOS.


As it is pretty beefy it can handle a lot of work with no heating, you can check iFix it pictures, it doesn't has any sort of heat dissipation solution.

Apple doesn't says too much about it, in technical terms. We don't know how fast it is and how to benchmark it.

But for sure it handles processes that once were CPU based.


Enjoy your MBA!
Ah, right.. that's why performance on a T2 machine is much better than the specs make it appear. So, time to stop relying on specs alone when shopping for T2-equipped machines?


Thank you for the information!
 

darkmatter343

macrumors regular
Sep 18, 2017
187
128
Toronto, Canada
As other's have pointed out, the T2 chip handle's numerous functions now. For a few of the primary things, it handles the encryption & encryption keys for your hard drive, keeps your finger print separate from the OS, etc.

As for the overall speed, you asked how a 1.6GHz CPU could perform the same as your 1.8GHz. It comes down to the CPU Architectural enhancements over the last few years. You can't compare clock speed for clock speed, the increases come from the improvements in design, as well improved efficiencies from within OSX.
 
  • Like
Reactions: revmacian

revmacian

macrumors 68000
Original poster
Oct 20, 2018
1,658
1,351
USA
As other's have pointed out, the T2 chip handle's numerous functions now. For a few of the primary things, it handles the encryption & encryption keys for your hard drive, keeps your finger print separate from the OS, etc.

As for the overall speed, you asked how a 1.6GHz CPU could perform the same as your 1.8GHz. It comes down to the CPU Architectural enhancements over the last few years. You can't compare clock speed for clock speed, the increases come from the improvements in design.
Thanks for that.. I had no idea.
 

Erehy Dobon

macrumors 6502a
Feb 16, 2018
528
372
The T2 Security Chip has a Secure Enclave coprocessor that handles secure boot, APFS encrypted storage and Touch ID. It also functions as the system management controller, image signal processor, audio controller and SSD controller.

In notebook computers, it handles the hardware microphone disconnect (mic is disabled when the lid is closed).

As in iDevices, the safety of the security features is increased by segregating these functions away from the CPU in discrete proprietary silicon.
 
  • Like
Reactions: revmacian

Fravin

macrumors 6502
Mar 8, 2017
250
126
Rio de Janeiro, Brazil
Yes, I do remember the NorthBridge.. I spent years building desktop computers before moving to Apple machines in 2014. So, the T2 actually aids in the job that was performed by the NorthBridge chip? I wonder if this tie-in is why the T2 runs a system called BridgeOS.
Yes it does. As you know how desktop computers were designed to work, you should remember the south bridge. That chip is still present even in our macs. But their work is less important.

The USB traffic is heavy to handle. Disks and SSDs are even tougher. And as mentioned before it still encrypts the whole data traffic.

BridgeOS is a clever name to a simple thing. It’s a tiny piece of software similar to BIOS in regular machines.
 
  • Like
Reactions: revmacian

Mike Boreham

macrumors 68000
Aug 10, 2006
1,679
366
UK
I don't think anyone has mentioned that it turboboosts to 3.6 GHz.

Install the free Intel Power Gadget to see how much time it spends turboboost while under load. Attached is an IPG screenshot of my 1.4 GHz 12" MacBook analysing chess moves at 3 GHz of Turboboost.

PS My MacBook is supposed to turboboost to 3.6 GHz, but that is the single core turboboost. Multicore turboboost is less, so you won't see 3.6 GHz on your Air.
 

Attachments

Last edited:

||\||

macrumors regular
Nov 21, 2019
171
454
In addition to what has already been mentioned, Apple tends to use hyperthreaded dual core processors, which acts as two additional virtual cores.
 

revmacian

macrumors 68000
Original poster
Oct 20, 2018
1,658
1,351
USA
Well, I think these machines are absolutely impressive.. I still can't understand why some people complain about them.

Thanks, everyone, for the education! @Mike Boreham Thanks for the IPG link, I'll install that a.s.a.p. and I completely forgot about turboboost.
 

AustinIllini

macrumors demi-goddess
Oct 20, 2011
11,582
8,291
Austin, TX
Well, I think these machines are absolutely impressive.. I still can't understand why some people complain about them.

Thanks, everyone, for the education! @Mike Boreham Thanks for the IPG link, I'll install that a.s.a.p. and I completely forgot about turboboost.
They're impressive for a high price. There are reasonable complaints and then some unreasonable complaints, IMHO. Overall, most of them are reasonable or have a reasonable answer.
 
  • Like
Reactions: revmacian

mj_

macrumors 6502a
May 18, 2017
625
321
Austin, TX
Your MacBook Air feels subjectively snippy because what you are using it for - Calendar, Mail, Notes, Reminders, Safari, Numbers, Pages, Affinity Designer, Affinity Photo, GIMP and iMovie - are basic workloads that any modern smartphone can handle. Regardless of the utter nonsense that has been posted here regarding Windows background processes even a $500 Windows laptop with a modern Core i5 CPU, 8 GB of RAM and an SSD would be more capable enough to handle these basic tasks with ease. The T2 chip has absolutely nothing to do with it. At all. Zero. Nada. Zilch. As has been mentioned it's a security chip with very limited and specific capabilities accessed and addressed by the Mac's firmware and the macOS operating system to offload a handful of very specific tasks, such as full-disk file encryption, on-the-fly encryption/decryption in general (think AES in hardware), TPM functionality, direct storage communication (which used to be handled by dedicated chips inside the SSD before, and which now allows Apple to use cheap dump NAND flash storage instead of more expensive SSDs), etc.

Keep in mind that your CPU can also turbo-boost from 1.6 up to 3.6 GHz for a few seconds of load. Scientific computing and gaming aside pretty much all computational tasks can be completed within seconds or, more often than not, even fractions of a second.
 
  • Like
Reactions: revmacian

Mike Boreham

macrumors 68000
Aug 10, 2006
1,679
366
UK
Keep in mind that your CPU can also turbo-boost from 1.6 up to 3.6 GHz for a few seconds of load. Scientific computing and gaming aside pretty much all computational tasks can be completed within seconds or, more often than not, even fractions of a second.
It will do it for more than a few seconds...see my post #11 above. There are threads in the 12" MacBook forum about sustained turboboost.
 
  • Like
Reactions: revmacian