Saturday, April 16, 2005

What if I told you that as well as enjoying the benefits of steadily improving software development, the PSP would, at some stage in the future (and without any modification), become capable of a hardware performance increase of fifty percent? That would be somewhat surprising, wouldn't it?

The PSP's CPU and bus have software-configurable clockspeeds. The CPU core is currently locked to a maximum clockspeed of 222MHz, and the bus (typically operating at half the CPU speed) is locked to a top speed of 111Mhz. The GPU (Graphics Processing Unit) operates at bus speed, in other words, up to the 111MHz cap. The advantage of having configurable clockspeeds in a portable device is that power consumption can be controlled by adjusting the clockspeed to the demands of the software at any given moment. When the PSP is rendering complex in-game graphics at around 222MHz it will necessarily chew up more power than it would need to when displaying a simple menu screen running at say 5MHz.

The PSP CPU's top clockspeed is 333MHz and the bus and GPU's top speed is 166MHz. See what's going on? Sony have deliberately locked the PSP's operating speed at exactly two-thirds of it's actual potential. They have an extra fifty percent of it's current performance ability simply waiting in reserve to be unleashed at a later date.

As I pointed out in my PSP Lowdown back in January, the graphical performance exhibited in PSP's launch titles looks like it's somewhere between PSone and PS2 standard. Now I understand why. The PS2's Emotion Engine (CPU) runs at 294.912MHz and it's Graphics Synthesizer (GPU) runs at 147.456MHz. While the PSP is clearly a more powerful device on paper, it's currently being restricted to a sub-PS2 standard of performance.