Raspberry Pi's GPU double the performance of iPhone 4S • Hacker News Board

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#41

Post by nextparadigms » Wed, Jan 25, 2012, 3:25 PM UTC

kevingadd wrote: post #16

Does the iPhone 4S actually use a Tegra 2? Everything I've read indicated it used a PowerVR GPU, just like every other iPhone, not a Tegra 2. The article seems fundamentally misguided and incorrect if this is the case. http://www.anandtech.com/show/4951/iphone-4s-preliminary-ben... says SGX543MP2.

Why do you think the author says iPhone 4S uses a Tegra 2? He doesn't say that.

I'm curious, though, is it really a fully open source computer? How does that work when it uses an ARM chip? Or does the open source part refer only to the OS? As soon as ARM replaces ARM11 with Cortex A7 or whatever, we should ask them to open source ARM11.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#42

Post by superrad » Wed, Jan 25, 2012, 3:31 PM UTC

NickPollard wrote: post #34

modeless wrote: post #8

Wow, that makes this thing a lot more interesting to me, if true. So many designs these days pair monster CPUs with underpowered GPUs it's almost embarrassing (especially as Apple continues to show that powerful GPUs are important for a good user experience). The 256 MB of RAM will be very constraining for any app trying to use all that power, though.

The PlayStation 3 has 256 MB of RAM and seems to do ok, as games like Uncharted and God of War show. It does mean you'll need to be more careful and considerate of how you use that memory though (and admittedly, on a console like a PS3 the OS takes up much, much less space).

Actually it has 512MB split into two pools for CPU and GPU.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#43

Post by TobbenTM » Wed, Jan 25, 2012, 3:35 PM UTC

nextparadigms wrote: post #41

kevingadd wrote: post #16

Does the iPhone 4S actually use a Tegra 2? Everything I've read indicated it used a PowerVR GPU, just like every other iPhone, not a Tegra 2. The article seems fundamentally misguided and incorrect if this is the case. http://www.anandtech.com/show/4951/iphone-4s-preliminary-ben... says SGX543MP2.

Why do you think the author says iPhone 4S uses a Tegra 2? He doesn't say that. I'm curious, though, is it really a fully open source computer? How does that work when it uses an ARM chip? Or does the open source part refer only to the OS? As soon as ARM replaces ARM11 with Cortex A7 or whatever, we should ask them to open source ARM11.

The ARM chip is not open source, and probably won't be at release either.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#44

Post by jharsman » Wed, Jan 25, 2012, 3:39 PM UTC

NickPollard wrote: post #34

modeless wrote: post #8

Wow, that makes this thing a lot more interesting to me, if true. So many designs these days pair monster CPUs with underpowered GPUs it's almost embarrassing (especially as Apple continues to show that powerful GPUs are important for a good user experience). The 256 MB of RAM will be very constraining for any app trying to use all that power, though.

The PlayStation 3 has 256 MB of RAM and seems to do ok, as games like Uncharted and God of War show. It does mean you'll need to be more careful and considerate of how you use that memory though (and admittedly, on a console like a PS3 the OS takes up much, much less space).

The PS3 has 256 MB system RAM and 256 MB dedicated video RAM. So it has twice as much RAM as the Raspberry Pi.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#45

Post by freehunter » Wed, Jan 25, 2012, 3:41 PM UTC

jmaygarden wrote: post #39

OhArgh wrote: post #26

Earlier quoted context omitted.

yea according to their site you can run it on 4 AA cells. Can you buy an IPhone for $25? http://www.raspberrypi.org/faqs

I can go out and buy an iPhone 4S today. Can you buy a Raspberry Pi at any price right now?

"It's better because it's available now" isn't an incredibly appealing argument when the price different is around $500.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#46

Post by noonespecial » Wed, Jan 25, 2012, 3:52 PM UTC

nextparadigms wrote: post #41

kevingadd wrote: post #16

Does the iPhone 4S actually use a Tegra 2? Everything I've read indicated it used a PowerVR GPU, just like every other iPhone, not a Tegra 2. The article seems fundamentally misguided and incorrect if this is the case. http://www.anandtech.com/show/4951/iphone-4s-preliminary-ben... says SGX543MP2.

Why do you think the author says iPhone 4S uses a Tegra 2? He doesn't say that. I'm curious, though, is it really a fully open source computer? How does that work when it uses an ARM chip? Or does the open source part refer only to the OS? As soon as ARM replaces ARM11 with Cortex A7 or whatever, we should ask them to open source ARM11.

I'd say its more closed source than open. The schematic is not released, the chip is a Broadcom ARM (not even for sale to the public), the GPU runs a binary closed blob. Even the boot sequence involves closed source binary "magic".

It runs linux. That's open. The rest, not so much. Its still awesome. It just is what it is.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#47

Post by falling » Wed, Jan 25, 2012, 3:52 PM UTC

Did anybody read the article? There is no demo or measurement, the manufacturer is promising, in an interview, that the SoC should perform like that.

Also, it's pretty confusing, mixing statements about Tegra 2 and iPhone 4S, which are quite different beasts.

It would certainly be impressive, but I'd rather wait for at least a demo, if not proper benchmarks, before throwing the party.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#48

Post by OhArgh » Wed, Jan 25, 2012, 4:14 PM UTC

st3fan wrote: post #35

OhArgh wrote: post #26

Earlier quoted context omitted.

yea according to their site you can run it on 4 AA cells. Can you buy an IPhone for $25? http://www.raspberrypi.org/faqs

That is pretty cool. You can't buy an iPhone for $25 but you also cannot buy a Raspberry Pi for $25 that has WiFi, 3G, BlueTooth a display, 64GB of flash and 512MB of memory :-) Anyway, I look really forward getting my hands on an RP.

Yea I was looking at the video of it running XBMC. Thinking of running it as a media center

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#49

Post by NickPollard » Wed, Jan 25, 2012, 4:14 PM UTC

jharsman wrote: post #44

NickPollard wrote: post #34

Earlier quoted context omitted.

The PlayStation 3 has 256 MB of RAM and seems to do ok, as games like Uncharted and God of War show. It does mean you'll need to be more careful and considerate of how you use that memory though (and admittedly, on a console like a PS3 the OS takes up much, much less space).

The PS3 has 256 MB system RAM and 256 MB dedicated video RAM. So it has twice as much RAM as the Raspberry Pi.

I'm aware of that, does the Raspberry Pi not have separate video ram? If not, that is my mistake - I didn't look closely and made an assumption. If it has a shared block of RAM (like the Xbox 360 Xenon, which has 512mb shared) then that is a significant difference - but still plenty to work wonders with.

Re: Raspberry Pi's GPU double the performance of iPhone 4S

#50

Post by theatrus2 » Wed, Jan 25, 2012, 4:24 PM UTC

jules wrote: post #28

andyzaharia wrote: post #4

Not really embarrassing, no one is comparing the power consumption. Apple could easily go to a more powerful GPU if their battery power allowed them. But I think the current 4S GPU is the one that fits for the current battery technology.

I wonder when mobile devices are going to contain FPGAs. They are often a factor of 100x power/performance better than CPUs/GPUs.

FPGAs are typically 5-20x worse in power consumption and max speed over a dedicated ASIC with the same logic. That is the price you pay for flexibility of being able to change your design at the drop of a hat.

For now, they are the low volume option (<1-10m units) if you need special interfaces. If all you are doing is number crunching a Gpgu would likely be a more effective option.