Pravin,
In addition to actually creating the graphics, the games have to do the physics/game logic. The degree to which the game uses the CPU for the actual game (vs graphics) logic depends on the complexity of the game. I'd be very interested to hear from real games programmers at software houses the CPU requirements for various games. My impression is that the game logic is rather minimal in terms of CPU demand, but it still does require CPU cycles. Of course, use of video and other multimedia will also tax the CPU.
When Cyrix starts saying their CPU can do 10 million meshed triangles per second, I think there are a lot of question marks about exactly what they mean. Obviously if that consumes all the CPU resources, you won't get that in any game. Also if various types of effects like texture mapping, fog, etc. require resources, what will be the actual output? I'd need to find out more about their design to see how many calc units they have and whether they can be used in parallel. Maybe they have constructed a good graphics pipeline in addition to their old core, but as said before, that's a lot of logic to stick in a chip, even at the smallest processes. Take a look at the real estate that 3Dfx uses for their boards: texture processors and pixel processors. I think it's obvious that you can't just replicate that logic and squeeze it into a nice Socket 7 footprint together with MPEG2/AC3 decoding! But then again I'm just a software guy ...
CPUs always have a balancing act between allowing more functions/units but still respecting the given real estate. In Intel's case, they reused their floating-point registers for MMX. You can have a long wish-list of things to accelerate in hardware, but practically I think they are assuming software working with their hardware. For example, their MPEG-2/AC-3 decoding would almost definitely not be totally hardware-implemented, but they'd probably use some Mediamatics software in conjunction with specific CPU features (probably something that speeds motion estimation).
-Bill |
