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Energy Efficient Graphics Processors?
An anonymous reader asks: "The trends for graphics hardware these days seems to be to draw more power and create more heat to get faster processors and push more polygons. Yet in the CPU arena chips like the Via C3 and Epia, Transmeta Crusoe and Astro, Intel Pentium M, and IBM/Motorola PowerPC (G3-5) seem to favor more power per megahertz and cooler runnings without significant performance loss. Is this just because of the nature of the CPU versus GPU? I understand a GPU die is almost entirely reserved for calculation while the CPU is only 20% of so for calculation. Or are the graphics chip makers merely refusing to innovate and take routes that would reign in out of control energy consumption because of the race for more polygons? What kind of architectural changes could be implemented to alleviate graphics card power gluttony?"
The latest Pentiums are power hungry hogs too, if you want the latest and greatest it's going to be less effienct than it could be. Low power consumption, size of heat sinks, volume of fans are less of a design constraint that the raw power of the chip.
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To hell with energy efficiency. I want my 1,000-watt GPU.
Sure, we can put a full foot of copper on our CPU's, but everybody screams and moans when Nvidia builds a cooler that takes up the adjoining PCI slot. Graphics cards are limited with the space they can take up for their cooling solutions, and they certainly pay for that in heat generation.
Most versions of the Geforce FX 5200 (non-Ultra) run fanless, which should speak to its relative energy efficiency. It also runs about as fast as a Geforce 3, unfortunately.
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Since when is the G5 efficient? It is as hot as any of the others. The G4 is a cool processor, but it runs at speeds like 1 GHz. Not that it doesn't make an awesome laptop (I've never had a complaint about mine) but it isn't exactly a model of efficiency.
You've compared high-end 3d desktop gamer cards which are excessive on heat and power to CPU chips which are designed for lower power low heat situations. The difference isn't nearly as pronounced with a more valid comparison on the CPU side, say a high end P4EE or Athlon64/Opteron. Also as you've stated, the GPUs are almost entirely dedicated to high-power processing, whereas the CPUs spend a lot of their silicon on other things. A high end GPU is generally superior to a high end CPU in terms of raw computing power. Therefore, it needs more power and makes more heat. If you forced intel or amd to build a CPU for you right now that had the raw compute potential of the latest high end cards, they'd have a hard time doing so without being just as hot and power hungry. All these things scale over time, but the demands of the user and his software scale up to meet it as well.
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There's a lot of sources to this.
The relitively frequent implimentation of new chips doesn't leave that much time to push for optimisaions on a hardware level to make more efficent chips.
Game makers push the bleeding edge, without preforming the optimisations they were forced to in the past. Gamers want cards that play the games full out.
"More Power" and "Bigger is better" are phrases that people ned to be thrown out of the public's mindset.
Um, that's probably why the poster didn't list the latest Pentium 4's in the CPUs he named. He didn't say ALL CPUs had any type of focus on power savings... let's stick to what's actually being discussed.
As gamer laptops get more popular, shouldn't we see new lower power GPUs with comparable muscle to the previous rev?
What's the power consumption like on a GPU that isn't doing much? Do they sleep like some CPUs can, or are they always going at full bore?
A few seconds on Google and I found nVidia's mobile offering. A few more seconds and I found this. Undoubtedly ATI has something similar.
Modern games usually don't need super-fast CPUs; even 2 GHz is just fine for most everything. Past that point, bus speed and GPU processing rate are your bottlenecks. So there's less demand for super-fast, super-hot main processors among the gaming crowd, who'd rather spend more on keeping their video card current.
I introduce this document as reference.
According to this, a PowerPC 970FX (the G5's being used in Apple's Xserves and the chip that will be in Apple's desktops this year) uses ~24.5W at 2.0ghz. So two of these are still only using half the wattage of a single Prescott chip, and obviously they can perform, too.
So yes, many of the chips he mentioned are not performance oriented, but the PowerPC 970FX certainly is, and it's safe to say it has made huge headway in power efficiency.
The biggest reason heat output keeps going up is that these gains only provide incremental benefits. To truly leverage the design changes, you have to run it as fast as it'll go ---> lots of heat.
The PowerPC isn't anything to scoff at, but if anyone could easily bump up the voltage & the multipliers, I'm sure a new G5 could be used to heat up your room in the winter.... and btw- Heat output does not increase linearly. The newer ATIs come with stock GPU & RAM voltages around 1.7 & 2.9. Unlike AMD/Intel/Nvidia/ATI *PUs, mac's aren't easily overclockable and when they are OCed they have very fine tolerances. Maybe if the powerpc chip put out a little more heat it could go faster?
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o0t!
but in the real world the case is a bit different. remember that globalwin cak38 with that delta 6800 rpm fan? it was nearly as loud as a helicopter. cpu coolers are starting to get quieter, with the help of wider heatsinks and wider fans (80-120 mm instead of 60 mm). but video cards are getting louder and louder because they are getting hotter and hotter.
sadly it is easier and cheaper to throw more raw power at the problem instead of designing more effecient.
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I tried a no-name GeForce 4 MX440 a couple of years back, but the display quality was awful. It was so poor I had to downgrade to 1280x1024 on my 19" Trinitron screen. After a few months the card broke and I went back to my TNT2 Ultra (Creative Labs) and back up to 1600x1200.
I was thinking about getting something fanless and by nVidia since their (binary-only) drivers are superb on Linux (I don't do the idealogical zealotry as much nowadays).
High-performance 3D is nice when you need it, but nowadays stuff is so powerful for under $100 that there's not much point to buying something really expensive. Some of us want a crisp, high-resolution display, flicker-free (70Hz+) without a great big noisy fan.
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Getting a bit old at this point, but it runs fanless. Power Color (not the best brand name in video) also sells a low profile version for those bastardized dell desktop cases.
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> GPU to the other side of the board to allow a much larger heatsink?
This will also help with the watercooling hose layout. It's pretty hard to hook up a waterblock between two cards and keep the hoses from collapsing.
The trends for graphics hardware these days seems to be to draw more power and create more heat to get faster processors and push more polygons. Yet in the CPU arena chips like the Via C3 and Epia, Transmeta Crusoe and Astro, Intel Pentium M, and IBM/Motorola PowerPC (G3-5) seem to favor more power per megahertz and cooler runnings without significant performance loss.
Have you ever used a PC based on a Transmeta Crusoe? They have significantly poorer performance that the CPU they are designed to replace. I'll take a hotter running, more power sucking Pentium any day.
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3 words : Tile Based Rendering
PowerVR used to make a GPU with the transistor count of a Voodoo 2 card, but with the power of GeForces 2 of its time.
These days, they are using this technology to build very low powered GPU for embed systems.
But they announced that they will soone start again to build GPU for SEGA's arcade systems.
Let's just hope they'll soon built a PC derivative of this arcade GPU.
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