Impressive GPU Numbers From Folding@Home 201
ludd1t3 writes, "The Folding@Home project has put forth some impressive performance numbers with the GPU client that's designed to work with the ATI X1900. According to the client statistics, there are 448 registered GPUs that produce 29 TFLOPS. Those 448 GPUs outperform the combined 25,050 CPUs registered by the Linux and Mac OS clients. Ouch! Are ASICs really that much better than general-purpose circuits? If so, does that mean that IBM was right all along with their AS/400, iSeries product which makes heavy use of ASICs?"
Re:GPUs are Specialized Parallel Computers (Score:5, Informative)
Here's a Wikipedia article [wikipedia.org] on general purpose GPU processing.
Folding is what's know as a rediculously parallel problem. That is, it can be broken up in to small subproblems that can be distributed among many processors with a minimal amount of communication among processors. It also benefits from not requiring a lot of branching (if/switch statements and such), which GPUs generally do not handle well.
Many problems, (I'd argue MOST problems) do not cater well to these kinds of restrictions. So, while a GPU is well suited to crunching away on pieces of the folding problem, it's going to be lousy at doing the day-to-day stuff you do with your computer.
Re:Lopsided Alright.. (Score:5, Informative)
Unless you are saying all CPUs are pegged at 99.9% use, or the GPU has memory three orders of magnitude faster then you're just looking at a effects that make a few percent difference here and there. The simple fact is the GPU is insanely faster at solving specific problems (3D processing) while it simply cannot ever run an operating system.
Remember: 1 GPU has more than one processor. (Score:5, Informative)
Standard CPU - 1 core (assuming dual cores get read as 2 CPUs).
448 GPUs x 56 = 25,088 effective processors all with on card memory.
25,050 CPUs x 1 core = 25,050 effective processors all dealing with system busses etc.
In short, if you're performing one simple task trillions of times, many very simple, highly optimized processors with dedicated memory do the job better than even a similar number of much more capable processors that have to play nice across a whole system.
And this ignores the number of old couple of hundred megahertz systems that people don't use anymore so hand over to the task vs. X1900s being the very high end of ATIs most recent line.
For massively parallel tasks like rendering pixels, folding proteins, compressing frames of a movie, etc. I'd absolutely love large quantities of a simple processor. For most other tasks, given present technology, I'd still side with fewer more able processors. Either way comparing 448 of something with 56 processors within it to 25,000 single processors and saying, "But 448 is SO much less than 25,000!" is an unfair comparrison.
Re:This is the perfect time... (Score:4, Informative)
Not true. You aren't taking into account Power Factor at all... Not that I'm surprised, as most people don't understand it.
With switching power supplies, it's common to see PF in the range of 0.4, as opposed to fully-resistive electric space-heaters (and incandesent lightbulbs) with a perfect 1.0 PF.
Residential customers are lucky, in that they don't get charged for PF losses by the power company, while companies certainly do. However, it's still highly ineffecient, even if you aren't paying for it directly.
And besides that, electric heating is almost always more expensive than conventional heating, like natural gas, or electric heatpumps.
Re:Uhhh... (Score:1, Informative)
Re:GPUs are Specialized Parallel Computers (Score:5, Informative)
Actually Linux users have good hardware: (Score:4, Informative)
I took (TFlop/active cpu)*1000 to get a readable number --
or Gflops/cpu
Windows is
Mac is
Linux is 1.21
And GPU is 65!
The source:
http://fah-web.stanford.edu/cgi-bin/main.py?qtype
The average Linux user proably has a decent AMD Athlon,
The average Windoze user has a P4 Dell.
Athlons just crunch the math better.
Re:PF losses are not losses in any real sense (Score:3, Informative)
Electricity isn't water, you can't return it to the source.
With a lower power factor, you're either forcing the power company to install huge banks of capacitors, or making the generators work that much harder for fewer watts actually delivered/used. That's practically the definition of "inefficent".
Re:PF losses are not losses in any real sense (Score:3, Informative)
A power factor of 0.6 does not mean 0.6 watts available for every watt sent. It means the capacity of the line is reduced to 60% of normal do to excessive circulating current. This is easy to see when you look at the rated output power of a typical wall socket, 120 VAC x 15 A = 1800 W, of which you can only use 1100 watts (actually 1080) for a computer load. 1100 watts is the largest common size for inexpensive uninterruptible power supplies for this very reason.
A 0.6 power factor should cause about a 66% increase in line losses for a given load.