> Desktop CPUs are about 3x faster than laptop CPUs
Maybe that’s an AMD (or even Intel) thing, but doesn’t hold for Apple silicon.
I wonder if it holds for ARM in general?
> Desktop CPUs are about 3x faster than laptop CPUs
Maybe that’s an AMD (or even Intel) thing, but doesn’t hold for Apple silicon.
I wonder if it holds for ARM in general?
Apple doesn’t really make desktop CPUs, though. Just very good oversized mobile ones.
For AMD/Intel laptop, desktop and server CPUs usually are based on different architectures and don’t have that much overlap.
What’s the difference between a M4 max and a “real” desktop processor?
It can’t be used as a space heater?
It’s not that it’s worse than a “real” desktop chip. In a way it’s better you get almost comparable performance with way lower power usage.
Also the M4 Max has worse MT performance than e.g. the 14900k which is architecture ancient in relative terms and also costs a fraction
Generally PCI-E lanes and memory bandwidth tend to be the big difference between mobile and proper desktop workstation processors.
Core count used to be a big difference but the ARM Procs in the Apple machines certainly meet the lower end workstation parts now. to exceed it you're spending big big money to get high core counts in the x86 space.
Proper desktop processors have lots and lots of PCI-E Lanes. The current cream of the crop Threadripper Pro 9000 series have 128 PCI-E 5.0 Lanes. A frankly enormous amount of fast connectivity.
M2 Ultra, the current closest workstation processor in Apple's lineup (at least in a comparable form factor in the Mac Pro) has 32 lanes of PCI-E 4.0 connectivity that's enhanced by being slotted into a PCI-E Switch fabric on their Mac Pro. (this I suspect is actually why there hasn't been a rework of the Mac Pro to use M3 Ultra - that they'll ditch the switch fabric for direct wiring on their next one)
Memory bandwidth is a closer thing to call here - using the Threadripper pro 9000 series as an example we have 8 channels of 6400MT/s DDR5 ECC. According to kingston the bus width of DDR5 is 64b so that'll get us ((6400 * 64)/8) = 51,200MB/s per channel; or 409.6 GB/s when all 8 channels are loaded.
On the M4 Max the reported bandwidth is 546 GB/s - but i'm not so certain how this is calculated as the maths doesn't quite stack up from the information i have (8533 MT/s, bus width of 64b, seems to point towards 68,264MB/s per channel. the reported speed doesn't neatly slot into those numbers).
In short the memory bandwidth bonus workstation processors traditionally have is met by the M4 Max, but PCI-E Extensibility is not.
In the mac world though that's usually not a problem as you're not able to load up a Mac Pro with a bunch of RTX Pro 6000s and have it be usable in MacOS. You can however load your machine with some high bandwidth NICs or HBAs i suppose (but i've not seen what's available for this platform)
The M4 Max’s bus width is 512 bytes, not 64.
Aha! That'll definitely get you to 546G/s.
The author is talking about multi-core performance rather than single core. Apple silicon only offers a low number of cores on desktop chips compared to what Intel or AMD offers. Ampere offers chips than are an order of magnitude faster in multi-core but they are not exactly "desktop" chips. But they are a good data point to say it can be true for ARM if the offer is here.
> Apple silicon only offers a low number of cores on desktop chips compared to what Intel or AMD offers.
* Apple: 32 cores (M3 Ultra)
* AMD: 96 cores (Threadripper PRO 9995WX)
* Intel: 60 cores (W‑9 3595X)
I wouldn’t exactly call that low, but it is lower for sure. On the other hand, the stated AMD and Intel CPUs are borderline server grade and wouldn’t be found in a common developer machine.
Yeah i9-14900 and 9950x are better comparisons, at 24 and 16 cores respectively.