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Friday, April 24th 2020

Dreaming Of ARM-based MacOS Desktops And Workstations

Many Apple developers and rumor followers have been expecting or hoping for ARM based macs in the near future. The performance of the A12 and A13 powered iPhone and iPad has surpassed the performance of their Intel powered mac laptops and desktops in certain areas.

The Verge: Apple will reportedly use 12-core 5nm ARM processor in a 2021 Mac:

Apple will release its first Mac powered by an ARM processor in 2021, Bloomberg reports. The company is thought to have three Mac processors in development as part of its Kalamata project, which are all based on the A14 chip that’s due to be used in this year’s flagship iPhone lineup. According to Bloomberg, the first of these processors will include a 12-core CPU with eight high-performance “Firestorm” cores and at least four energy-efficient “Icestorm” cores.

Bloomberg’s report offers a lot of technical details on the form Apple’s chips could take:

  • Three Mac System-on-Chip (SoC) designs based on the A14 processor are currently in development, and work has also started on a Mac SoC based on next year’s iPhone processor. Bloomberg speculates that Apple is planning to keep both its laptop and mobile chips on the same development cycle.
  • The Mac chips will reportedly be manufactured by TSMC based on a 5nm fabrication process.
  • The first of these chips will feature eight high-performance CPU cores and at least four energy-efficient cores, for 12 cores in total. The A12Z chip used in the current iPad Pro has eight cores: four high performance and four energy efficient.
  • As well as a CPU, the SoC will also include a GPU.
  • ARM Mac computers will continue to run macOS rather than switching to iOS, similar to the approach taken with existing Windows laptops that use Qualcomm ARM processors.
  • Bloomberg speculates that Apple’s first ARM-based machines will be lower-powered MacBooks because its own chips won’t be able to match Intel’s performance in its higher-end MacBook Pros, iMacs, and Mac Pro computers.
  • Back in 2018, Apple reportedly developed a prototype Mac chip based on that year’s iPad Pro A12X processor. The success of this prototype is thought to have given the company the confidence to target a transition as early as 2020.

mjtsai: ARM Macs in 2021:

I expect the ARM transition to be accompanied by removal of lots of APIs, so developers will have to contend with that, as well as porting and testing their own code, and dealing with any dependencies that have broken.

While everyone has mostly been focused on the first machine a lower powered ARM mac could be (likely the MacBook), they are quick to say that Apple’s ARM chips couldn’t compete with the high-end Intel mac laptops or Intels Xeons in the iMac Pro and Mac Pro. This has left me wondering what a high-powered workstation class macOS ARM processor could be like.

While I do have a travel laptop, almost all of my work is done on a 2015 iMac1. This has left me to wonder what a workstation class ARM-based mac would be like and how long it might be until it’s available.

Fortunately, some ARM powered workstations and servers2 already exist for comparison.

AnandTech: Arm Development For The Office: Unboxing an Ampere eMag Workstation

Inside the system is a 32-core Ampere eMag server, with 256 GB of eight-channel DDR-2666 memory, a 500GB WD Black SN750 NVMe SSD, a 960 GB Micron 5300 Pro SATA SSD in the rear, a Corsair VS 650W power supply, and an AMD Radeon Pro WX 5100 graphics accelerator…

The eMAG 8180 is a 32-core design running at 2.8 GHz with a turbo up to 3.3 GHz, with a TDP of 125 W. This is a first generation eMAG, which uses the old AppliedMicro Skylark microarchitecture, a custom design of Arm v8 with 32 MB of L3, 42 PCIe lanes, and eight memory channels. Avantek offers the system with three optional graphics cards: AMD FirePro W2100, a Radeon Pro WX 5100, and the NVIDIA Quadro GV100.

I am really curious to see how this CPU benchmarks against some similar wattage Xeons. This seems really promising for a design and development workstation.

This Ampere eMag Workstation can be configured on their website and starts at $3,938. A setup like this could be comfortably within the Mac Pro price range.

AnandTech: Next Generation Arm Server: Ampere’s Altra 80-core N1 SoC for Hyperscalers against Rome and Xeon:

On top of the 80 cores, the SoC will also have eight DDR4-3200 memory channels with ECC support, up to 4 TB per socket. There are also 128 PCIe 4.0 lanes, with which the CPU can use 32 of them to hook up to another CPU for dual socket operation. The dual socket system can then have a total of 192 PCIe 4.0 lanes between it, as well as support for up to 8 TB of memory. We are told that it’s actually the CCIX protocol that runs over these PCIe lanes, which means 25 GB/s per x16 linkup. That’s good for 50 GB/s in each direction.

Each of the 80 cores is designed to run at 3.0 GHz all-core, and Ampere was consistent in its messaging in that the top SKU is designed to run at 3.0 GHz at all times, even when both 128-bit SIMD units per core are being used (thus an unlimited turbo at 3.0 GHz). The CPU range will vary from 45W to 210W, and vary in core count - we suspect these SKUs will be derived from the single silicon design, and it will depend on demand as well as binning as to what comes out of the fabs.

This definitely sounds promising. 3GHz x 80 cores would be amazing. The 45W TDP of the lower spec CPUs (barely) matches the 16” MacBook Pro TDP which is also 45W. The high end 210W spec is also very close to the 2019 Mac Pro Xeon W TDP of 205W.

While I have no idea what an Apple designed workstation CPU would be like, it should be noted that both of the above examples from Ampere are being built on TSMC’s 5nm process which is the fab and production company that Apple is also going to be using.

A Brief Note on Software: Unfortunately, a lot of design tools are still single-core or barely multi-core capable. Design tools aren’t ready for this massively parallel future… yet.

I hope that once more 64 core (and more!) CPUs become standard in design workstations it will motivate software to take advantage of more parallel computing.

1: The last two generations of iPhone have a faster single core speed than my iMac. The iPhone 11 even has a 30% faster single core benchmark. Regarding multi-core, the 2018 iPad Pro is 9% faster than my iMac.

2: ARM powered servers have been making some big gains for their great performance per watt. I wonder if there’s a small possibility of an ARM-based Xserve returning. At least, I can dream about it.