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Ageia's PhysX physics processing unit


Smithereens gone wild
— 12:00 AM on June 22, 2006

I'VE HAD THE CHANCE to spend a few days playing with a PhysX card from Ageia, and there is much to tell, though not much one can do with the hardware just yet. I did find some interesting ways to test the PhysX card, and the results may enlighten us about the prospects for physics acceleration in custom hardware. Read on to get my take on Ageia's new physics processing unit.

The hardware
The PhysX card itself looks an awful lot like a video card, with its centrally located cooler and four-pin Molex aux-power connector, but don't be fooled. This card's metal slot cover is devoid of outputs, and the golden fingers extending from the board are intended to slip into a humble 32-bit PCI slot. This card is made for crunching numbers, not driving a display.


A pair of Ageia partners, Asus and BFG Tech, have brought PhysX cards to market. The board you see above is the BFG Tech version, and it comes with 128MB of Samsung GDDR3 memory chips attached. These chips run at an effective data rate of 733MHz on a 128-bit interface, which works out to 12 GB/s of memory bandwidth dedicated solely to physics processing.

Pop the cooler off of the card, and you'll find the star of the show, the PhysX chip, residing below.


This custom-designed physics processor measures roughly 14 mm by 14 mm, or 196 mm2. TSMC packs about 125 million transistors into this space when it fabricates the chip using its 130 nm manufacturing process.

The itty little rectangular chip you see situated below the PhysX PPU, by the way, is not a bridge chip like you might see on some PCI cards these days. This chip comes from Texas Instruments and is used to step down the voltage coming in from the PCI bus. As a low-voltage 130 nm device, the PPU probably needs its assistance in talking to the relatively high-voltage PCI bus.