What made the PS3 useful in super computing and why didn’t the PS4 find the same use?
In: Technology
There were two reasons the PS3 was so useful in supercomputing. The first reason was that the Cell Processor that Sony used as the CPU in the PS3 was very good at multitasking, which made it ideal for stringing multiple PS3s together to create one very powerful device.
However, the biggest reason was cost. When the PS3 came out, it had very powerful components for the time, and to make it so that anybody could afford to buy the PS3, Sony took a huge loss on each unit, hoping to make up for that with profits from game sales. I believe the PS3 was $600 at launch, but even with a massive economy of scale it cost Sony something like $800 or $900 to build each unit. That meant that for $600 consumers could get computer components that would cost them double that or more if they bought them at retail.
So essentially the PS3 was so good for supercomputing because Sony was subsidizing your supercomputer.
For it’s time it had some pretty powerful hardware, plus the original version (pre PS3 slim) had good Linux support which made networking them together and running it as a supercomputer pretty easy. Sony removed that support from the PS3 Slim version (due to the ability to hack the console through this support) which caused the “downfall” of super computing with a PS3. PS4 also lacked this support so it wasn’t very enticing for anyone to even attempt using the PS4 in the same way.
The PS3’s Cell processor is really unlike any other CPU out there, in that it’s sort of this Frankenstein hybrid between a traditional CPU and a modern GPU. It does this through a process called parallel processing.
So a modern GPU works by having a lot of simple processing cores designed to perform a limited number of tasks very quickly. Usually crunching fairly straight forward math like geometry and physics equations. Meanwhile, a CPU uses a limited number of more complex processing cores. So while they’re not as fast, they’re capable of executing far more complicated and diverse sets of instructions than a GPU can. One way to imagine it is a master craftsman making say custom furniture, versus a bunch of guys doing simple, repetitive tasks on as assembly line.
Games require a lot of simple, repetitive math processing to render an image. Turns out, so do a lot of scientific calculations. Like running physics simulations. GPUs are very good at doing these tasks.
So where does the Cell fit into this? Well, the it was created at a time before GPUs were capable of running any other code besides graphics. So what the Cell did was combine a PowerPC-based CPU core with eight simple cores to run parallel processing tasks. Called the Power Processing Element (PPE) and Synergistic Processing Elements (SPE) respectively.
The SPEs resemble modern GPU cores in they’re specifically design to handle a lot of simple math very quickly. Which made the chip ideal for doing basic math calculations. So it was quickly exploited by organizations like Folding@Home, which used the console’s downtime to run protein simulations far faster than could be achieved with a standard CPU. The US Air Force also bought a cluster of PS3s to run physics calculations. Since they were powerful, but also relatively cheap compared to traditional hardware of the same capability. And at the time, you could also install Linux on the console to run general purpose applications.
This was fairly short lived though as one the same month the PS3 lunched, Nvidia released the 8800 GTX and Tesla GPUs, which moved to a new chip design, called the Unified Shader Model, that you could run general purpose code on in a similar manner to how the Cell worked. And it was twice as powerful as PS3 while costing about as much. So the Cell was quickly rendered obsolete for both consumer and power computing tasks beyond a few outlying cases.
All modern GPUs use the Unified Shader Model. So even though the PS4 has a weaker CPU, its GPU can run code other than just graphics. So a lot of things like physics are offloaded to it. Sort of like the Cell split in two.
Developer here,
The PS3 used a Cell processor – the details aren’t important, but it was mostly a math processor, pretty powerful for its time, and most importantly, cheap.
The PS4 is an Intel x86 processor just like in your desktop and laptop. It’s the same processor as found in the current generation Xbox. The math processing power is in a video card found in the console.
Basically the cost and common architecture made it no longer competitive in this application. I can buy x86 CPUs en masse from anywhere. If you wanted to use the Cell processor, it wasn’t a generally available CPU. You could special order them and develop your own hardware platform, or you can just buy a bunch of PS3’s. But now days if you wanted to build a cheap number cruncher, you would invest in GPUs. And you don’t need latest and greatest, power consumption is the biggest concern of modern super computing.
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