Apple is set to unveil its long-awaited Mac transition from Intel to ARM processors today at its online WWDC 2020 keynote, and analyst Ming-chi Kuo has issued his predictions for the first Macs that will use the new Apple-designed processors. His research note was reported on by MacRumors, 9to5Mac, and AppleInsider.

First of all, Kuo says the last new Intel-based Mac ever will be a brand new iMac design with thinner bezels and a 24-inch display. This iMac is said to be planned for a release in Q3 2020, but an ARM version will follow it in the first quarter of next year.

The first ARM Mac is likely to be a 13-inch MacBook Pro in Q4 2020 or Q1 2021, Kuo says; the form factor is believed to be similar to the current model. Production of the Intel version will reportedly cease once the ARM model is introduced, though there’s no word on whether the same will be true for the iMac. Kuo also believes a new ARM-based MacBook design will start production in mid-2021.

Apple’s transition to a fully ARM-based lineup will take 12 to 18 months, according to Kuo. The analyst expects the new ARM machines to outperform their Intel predecessors by 50 to 100 percent, though the actual performance will of course depend on what Apple decides to prioritize with the new designs. If a hypothetical Apple processor is 50 percent more efficient than a given Intel chip, for example, that headroom could theoretically be spent on extending battery life at similar speeds or on achieving faster performance within the same thermal envelope.

Apple choosing the MacBook Pro and the iMac as its first ARM-based Macs would mirror the history of the last Mac processor transition. At WWDC 2005, Apple announced that it would move from PowerPC processors to Intel for performance reasons, then in January 2006 the company released its first Intel-based Macs: an iMac with a Core Duo inside the old G5 chassis, and the all-new MacBook Pro that replaced the PowerBook G4.

As such, it’s likely that actual ARM-based consumer Mac hardware won’t be shown off at WWDC 2020. Apple may instead make test hardware available to developers so that software can be adapted to run on ARM processors in time for the computers’ launch.