What made the PS3 useful in super computing and why didn’t the PS4 find the same use?
In: Technology
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.
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