Picking apart the Pixel –
Is the “Pixel Neural Core” a single chip or two chips?
iFixit has gotten its hands on Google’s newest flagship, the Pixel 4 XL, and hastorn it apartfor our viewing pleasure.
Compared to the Pixel 3 XL that wastorn down last year,a lot has changed. The Pixel 4 has an entirely new internal design, with a skinny, tall battery and chips on the side, whereas the Pixel 3 had a fat, short battery with most of the chips in the top of the phone. The reason for the difference is most likely the fingerprint reader: the Pixel 3 XL had a rear fingerprint reader with some stringent placement requirements, and now with no fingerprint reader at all, Google no longer has to design the phone around its location (although an in-screen fingerprint reader would have removed this limitation, too).
iFixit found that the (sometimes) 90 Hz OLED display is, to the surprise of no one, made by Samsung. Samsung now makes both the 90 Hz display for the Pixel 4 and for OnePlus devices like the 7 Pro and 7T. As iFixit notes in its teardown and as we noted in ourGalaxy Note 10 coverage, it’s really baffling that Samsung is letting its competitors beat it to market with its own 90 Hz displays. Maybe the Galaxy S 11 will finally see a speedy Samsung display in a Samsung phone.
There are a few special components in the Pixel 4 to take a look at. The first is the Google-developed Soli radar sensor, which the Pixel 4 mostly just uses for an air-gesture system. There just isn’t a lot to see here, with iFixit describing it as “a tiny featureless rectangle with no moving parts.” There seem to be four squares on the little circuitboard, with one separated from the other four — and that somehow makes the gesture-detection magic happen. The second interesting new component is the Pixel 4’s face unlock system, which, in teardown form, looks just like the pictureGoogle shared earlier.
There are a few surprises, too. iFixit found aKnowles 8508 Aquad-core audio processor in the Pixel 4, which sounds like it would help with all the on-board voice processing the Pixel 4 does. The Pixel 4’s next-gen Google Assistant, the new voice recorder app, and the live caption feature all rely on local voice-to-text processing. This chip uses an ARM Cortex M4 and a collection of DSPs, and it is not listed on the Pixel 4 spec sheet. Whatislisted on the Pixel 4 spec sheet is something called a “Pixel Neural Core,” and while everyone assumes this is a single physical chip developed by Google (as was the casein years past), the company as never gone in-depth explaining what the “Pixel neural Core” is. The best description we’ve gotten is from thePixel 4 launch blog post, which says, “Pixel Neural Core is the engine for on-device processing, always-on computing, and machine learning, meaning more tasks are done on the device for performance and privacy. ” Note that thisdoes notdescribe the Pixel Neural Core as “a chip,” only “an engine,” and it’s possible that the Neural Core isn’t a single chip — it may be a collection of chips and software that includes this Knowles audio processor. They certainly seem to have significant overlap.
Another mystery chip we can tentatively place in the “Pixel Visual Core” category is an unknown blob of Samsung RAM that lives on the motherboard in addition to the system RAM. In smartphones, RAM is usually stacked on top of an SoC, so iFixit speculates that there is a second chip hiding under this RAM. The site notes there is “a big ‘P'” on the chip, perhaps indicating that if the “Pixel Neural Core” has a main chip, this is it.
As far as repairability goes, iFixit praises the use of standard Torx fasteners and stretch-release battery adhesive but dings the Pixel for a glued-on back panel, a difficult-to-replace display, and an all-glass construction. It scores a 4 out of 10.
Listing image byiFixit
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