Maybe it's because they don't want to buy anything, or maybe it's because they don't understand the technology, but every day there are several posts on this forum that follow the same old lines "I won't buy anything until they utillize my extra CPU core". So here are the reasons why that just doesn't work:
1. People keep saying "just use the CPU for physics". Well, that's what developers are doing right now! Physics are nothing new, and they do exist in today's games, calculated on the CPU. But we've hit a wall with this method of physics procesing. A CPU simply doesn't have the required power to do physics any better than what we have now. But what about dual-core? Well, take the number of objects a CPU can handle (around 2,000) and add 80% (dual-core CPUs aren't 100% efficient). Add 280% for quad-core. You still will be nowhere near the 30,000+ objects that a PPU or GPU can handle.
2. There are technical reasons why a CPU cannot do physics while a GPU can. It's all about pipelines. A typical GPU has between 24 and 48 pipelines. This allows it to do many calculations all at once or in parallel. A CPU, however, has very few pipelines. This means that a CPU must do instructions in a sequential manner. Physics calculations require massively parallel processing to perform well. Ideally, every object should be tracked at the same time. A GPU and PPU can do parallel processing, but a CPU isn't very good at it.
3. Here is a constructed mathematical argument:
We know that physics calculations and graphics calculations require the same type of processing power. This is why a GPU can be used to do accelerated physics.
It is obvious that we can make the statement "If a CPU can do physics, then it can do physics" using the reflexive property.
Since we know that graphics = physics as far as processing goes, we can substitute "graphics" for "physics" in that statment: "If a CPU can do physics, then it can do graphics".
We know that a CPU cannot do graphics in real time. You can verify this by attempting to run any game without a GPU installed, or with hardware acceleration disabled.
So then, we have this:
If a CPU can do physics, then it can do graphics.
A CPU cannot do graphics.
Therefore, it cannot do physics.
Now, for all you math geeks out there, that is called "denying the consequent" or the Modus Tollens argument method. It is one of two valid ways to draw a conclusion when given two premises, one of which is a conditional.
So that's why a CPU is no substitute for a GPU or PPU when it comes to physics. Can something at least be put in the FAQ about this? I have to restate this argument every day because someone else comes along and says "use the CPU'".
Disclaimer: When I say "a CPU cannot do graphics", I am not referring to raytracing or pong. I am referring to shader graphics of the quality and quantity found in today's games (not including turn-based and/or 2D games, obviously). I understand that raytracing technologies are being developed that work on a CPU and that very old games used the CPU for rendering. Likewise, when I say "a CPU cannot do physics", I am referring to accurate, realtime physics of the type and quantity promised by AGEIA, NVIDIA, Havok, and ATI (i.e. cloth, friction, tens of thousands of objects...). This has confused a few people, so I thought I would clear it up right here.
1. People keep saying "just use the CPU for physics". Well, that's what developers are doing right now! Physics are nothing new, and they do exist in today's games, calculated on the CPU. But we've hit a wall with this method of physics procesing. A CPU simply doesn't have the required power to do physics any better than what we have now. But what about dual-core? Well, take the number of objects a CPU can handle (around 2,000) and add 80% (dual-core CPUs aren't 100% efficient). Add 280% for quad-core. You still will be nowhere near the 30,000+ objects that a PPU or GPU can handle.
2. There are technical reasons why a CPU cannot do physics while a GPU can. It's all about pipelines. A typical GPU has between 24 and 48 pipelines. This allows it to do many calculations all at once or in parallel. A CPU, however, has very few pipelines. This means that a CPU must do instructions in a sequential manner. Physics calculations require massively parallel processing to perform well. Ideally, every object should be tracked at the same time. A GPU and PPU can do parallel processing, but a CPU isn't very good at it.
3. Here is a constructed mathematical argument:
We know that physics calculations and graphics calculations require the same type of processing power. This is why a GPU can be used to do accelerated physics.
It is obvious that we can make the statement "If a CPU can do physics, then it can do physics" using the reflexive property.
Since we know that graphics = physics as far as processing goes, we can substitute "graphics" for "physics" in that statment: "If a CPU can do physics, then it can do graphics".
We know that a CPU cannot do graphics in real time. You can verify this by attempting to run any game without a GPU installed, or with hardware acceleration disabled.
So then, we have this:
If a CPU can do physics, then it can do graphics.
A CPU cannot do graphics.
Therefore, it cannot do physics.
Now, for all you math geeks out there, that is called "denying the consequent" or the Modus Tollens argument method. It is one of two valid ways to draw a conclusion when given two premises, one of which is a conditional.
So that's why a CPU is no substitute for a GPU or PPU when it comes to physics. Can something at least be put in the FAQ about this? I have to restate this argument every day because someone else comes along and says "use the CPU'".
Disclaimer: When I say "a CPU cannot do graphics", I am not referring to raytracing or pong. I am referring to shader graphics of the quality and quantity found in today's games (not including turn-based and/or 2D games, obviously). I understand that raytracing technologies are being developed that work on a CPU and that very old games used the CPU for rendering. Likewise, when I say "a CPU cannot do physics", I am referring to accurate, realtime physics of the type and quantity promised by AGEIA, NVIDIA, Havok, and ATI (i.e. cloth, friction, tens of thousands of objects...). This has confused a few people, so I thought I would clear it up right here.