by Charles Ying

Archive for December, 2009

Can I get a JooJoo with a GPU?

Tuesday, December 8th, 2009

From watching videos of JooJoo, UI latency and scrolling performance look awful.

It seems that all rendering is done on the CPU, when it should’ve been on a GPU accelerated compositor or tiled surface manager.

That would save significant battery life (which we haven’t heard anything about) and really kick ass at performance.

Offloading rendering to the GPU also frees you up to, oh, say, reliably detect touch input events.

System on Chip GPU + CPU combos are fairly inexpensive parts these days. Even with a GPU as simple as the first gen iPhone PowerVR MBX lite would’ve had reasonable performance.

UI latency and scrolling performance make all the difference in multi-touch form factor devices. A true multi-touch contender needs to get this right.


I just realized that JooJoo plays video smoothly at 1080p. So they definitely have a GPU or DSP in there. They’re so close, they just need to get the software up to snuff, maybe with Clutter?

More Reading: On Mobile Phone OS Design and GPUs

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On Mobile Phone OS Design and GPUs

Wednesday, December 2nd, 2009

Mobile phones have really big screens.

Tablets will have even bigger screens.

If you want your mobile phone OS to matter in 2010, you’d better optimize for rendering graphics on the GPU.

GPUs are far more power efficient and faster at drawing graphics. As mobile device screens get really large, drawing the graphics “old school” on the CPU is moving from “unacceptable” to “impossible” pretty quickly.

Today, Motorola Droid runs at about half the frame rate of iPhone 3GS. The GPU in both is a PowerVR SGX 530 series chip.*

A PowerVR SGX 530 has a fill rate of 200 million pixels per second. That means Motorola Droid’s GPU could theoretically drive 8 full screen refreshes at 60 fps on a Droid-sized (WVGA) screen. All without the CPU’s help.

Parts of Android’s graphics subsystem seem to be GPU accelerated, but more is needed.

Imagine if the Android UX ran at a rock solid 60 fps. Then, I think we’d have something pretty sexy.

I wonder if Apple’s PA Semiconductor unit is designing GPUs instead of CPUs?

* It’s unclear what the exact model of the iPhone 3GS GPU is, and so the exact fill rate is not known… (though if it were, say, a PowerVR SGX 535, its fill rate would be 400 million pixels per second)

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