(Pocket-lint) - It's pretty obvious that Apple is working on Macs powered by its own A Series chips. It's been rumoured for years during which analysts and journalists close to the company have repeatedly stated the ambition. 

Now Bloomberg's Mark Gurman has said the first Mac based on an ARM-design processor (which will no doubt be one of Apple's own-brand chips) is slated for 2021.

The benefit is longer battery life and more efficiency generally, which isn't news - we know ARM-based chips are good at that. If you ask us, we think it would have to a MacBook Air-style ultraportable.  

Gurman says the processor is codenamed Firestorm and will be an eight-core chip. 

The 5nm chip will apparently once again be manufactured by TSMC, who make the Apple-branded processor that's in your iPhone or iPad now. Apple is apparently exploring 12 core chips for the future.

We know that Apple has previously tested macOS on ARM internally previously. 

The doubt in this, of course, is that the iPad Pro is now more like a computer than it's ever been - will Apple really go so far as to make the Mac a more phone-like experience when it's already doing that with iPadOS? 

Also, the performance of Windows on ARM using Qualcomm chips has been less than impressive. The systems have delivered great battery life but there have been issues with sheer power as well as app compatibility and more.

Of course, Apple has form with moving macOS (then called Mac OS X) to a different processor, as when it moved from PowerPC to Intel 15 years ago.

The move could be another step toward unifying apps on iOS and macOS, which we've already seen with Catalyst apps like Apple News which are essentially iOS/iPadOS apps on the Mac desktop. 

There is also another potential reason for the continued rumours of course - to keep Intel on its toes. 

Writing by Dan Grabham.