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Comment by toast42 | Hacker News Reader

Assuming the claims are correct (5x performance, 10x less power), what's stopping this from going mainstream?

The results aren't good enough to compete in games. Gamers don't care if the reflections and shadows are more authentic if the shading as a whole regresses by several generations.

Just compare the subjective quality of their "accurate rendering" to what that Nvidia GPU they showed can do with cheap approximations:

https://www.youtube.com/watch?v=BAAPTiuFdwU https://www.youtube.com/watch?v=slc--V2pi5c

https://www.youtube.com/watch?v=vfZD22zMnUY https://www.youtube.com/watch?v=UwEuSxAEXPA

The results aren't good enough to compete in games that require an expensive dedicated graphics card that costs more than the device this gpu will go in. FTFY.

Compared to any current phone/tablet GPU, it's going to be a big step up.

Going by their claim of "10x lower power than 980ti" this PowerVR card is burning through 25 watts, so it being a visual step up from Snapdragon and Apple SoCs which draw 3-4 watts for the CPU and GPU combined isn't particularly impressive.

From the article:

> The PowerVR GR6500 is a mobile GPU. Its die size, GFLOPS performance, bandwidth requirements and power consumption mean that it is comparable to the GPUs already available in smart phones today. But compared with a console GPU or looking towards the smart phones and handheld devices of the future, we see a roadmap that scales in capabilities and performance well beyond the GR6500’s specifications. The PowerVR Ray Tracing technology is fundamentally scalable and the efficiency actually increases as we move to more and more powerful cores.

28nm die size is previous gen mobile GPUs. But would be great to see how this performs for desktop use when they shift to smaller process nodes and scale it to match power consumption and cost with say, GTX 980

Ray-tracing is pretty different from polygon rasterization, so to perform well and take advantage of the technology, I think games are going to have to be written from the ground up with ray-tracing in mind. That's hard to do when game developers use complex frameworks and tools that are designed around rasterizing polygons.

(It's the same kind of problem as you'd run into if you wanted to do game development in Haskell or Rust. There's no reason why that couldn't work in principle, but things get harder when you step off the well-traveled path.)

As an example, polygon rasterization is sensitive to the number of polygons, but it doesn't matter very much where they or how they move around.

Ray-tracing, on the other hand, is relatively insensitive to the complexity of the scene, but it's more sensitive to what's on screen and visible right now, and how much of the screen it takes up. Also, objects have to be stored in 3-dimensional tree structures for efficient access, and those trees have to be re-built when things move. So, rendering the Statue of Liberty in high resolution is fine, but rending a million snowflakes is problematic.

Getting good performance means being conscious of different tradeoffs, and it takes time to figure out a good balance.

Excellent summary. Thanks. Hopefully this push towards ray tracing will result in more work done in addressing the points you raise.

The same claim could be made for PowerVR offering in general: why doesn't PVR go mainstream. I mean: you could get PS3 level output for probably tenth the energy so why not? Except that it is mainstream with roughly 50% mobile market share. :) The bottom line is: IMG doesn't produce silicon (except for internal use) so you need a partner to go "mainstream" (whatever that means). You're showing your IP on e.g. CES to find those partners (or to validate existing partners' investment in the platform). That's how IP companies operate, unless they are the de-facto monopoly in some segment.

10x less power compared to a gtx980ti, which is 250 watts TDP. That puts their device at 25 watts, which doesn't fit into the power envelope of any popular device form factor. A tablet should be 10 watts maximum at peak load, a phone should be closer to 1 watt. And it can't compete with desktop hardware either.

This is assuming that they run the 980ti maxed out, which might not be the case. If it isn't maxed out, it's a bit of a silly comparison.

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