The recent launch of Apple’s new MacBook Pro lineup was arguably overshadowed by the Apple Silicon powering the devices. The power of the new M1 Pro and M1 Max chips has been the talk of the tech blogosphere since Apple chip guru Johny Srouji detailed their capabilities. While Intel’s new 12th-gen Alder Lake laptop chips look to be competitive in terms of outright performance, their performance-per-watt looks to be around 50 percent lower than what Apple is able to achieve.
Hector Martin, a well-known developer in the process of porting Linux to Mac, tweeted that he has found numerous references to multi-die configurations in the macOS driver code base. In the same tweet, he added that the IRQ (interrupt request) controller “is very clearly engineered with a (currently unused) second half for a second die)”. This is not to say, however, that Apple could also use fabric interconnect outside the dies to connect them together for a total of 40 CPU cores and 128 GPU cores.
When considering the performance of a two die M1 Max configuration for a Mac Pro, it is simply not enough horsepower on the GPU side (CPU side is not a concern). The best performing GPU in the current Mac Pro is a Radeon Pro W6800 Duo MPX Module that uses two linked GPUs over AMD’s Infinity Fabric interconnect to produce up to 30.2 TF of single-precision compute. Two M1 Max dies would have a total of 64 cores for 20.8 TF of single-precision compute. This is clearly insufficient and points to the four M1 Max die configuration Gurman has alluded to which would produce 41.6 TF of compute.
However, the one wrinkle in these numbers is that the current Mac Pro can support up to two Radeon Pro W8600 Duo MPX Modules which can produce up to 60.4 TF in tandem. One can speculate that while Apple may well adopt a four M1 Max configuration (if not also a two M1 Max configuration for an entry-level Mac Pro), that it may also have to consider a discrete GPU option and/or something similar to the Afterburner accelerator it currently offers as an option. Apple has already demonstrated it can blow away people’s expectations with its Mac silicon, so anything could be possible by the time the next Mac Pro launches sometime in 2022.