Does Cell = PPU in Physics Calculations?

[Frank]

Some other questions: what is the CPU to do while the PPU does it's job, and what exactly would be the large difference with having the SPU's do all that?

Like, Heavenly Sword now uses the CPU and about 1 SPU, right? What would be the point in adding yet another chip that is functional almost identical to the hardware that isn't even used at the moment, and having the CPU wait while that does it's job?

I really don't see the point.

 

[London Geezer]

Some other questions: what is the CPU to do while the PPU does it's job, and what exactly would be the large difference with having the SPU's do all that?

Like, Heavenly Sword now uses the CPU and about 1 SPU, right? What would be the point in adding yet another chip that is functional almost identical to the hardware that isn't even used at the moment, and having the CPU wait while that does it's job?

I really don't see the point.

Well... PCs don't have Cell... PPU is for PCs, not for PS3.

 

[Frank]

Well... PCs don't have Cell... PPU is for PCs, not for PS3.

Yes, and Sweeney says, that you can have great physics when you buy and use their game engine on all the platforms, but that you would need to buy a PPU for the PC.

It was mostly a reaction to the post by gurgi, and the general idea that a dedicated PPU will pwn a PS3, just because it's specially made for that and Sweeney might have meant that, if you look hard.

And totally on-topic.

 

[London Geezer]

Well... PCs don't have Cell... PPU is for PCs, not for PS3.

Yes, and Sweeney says, that you can have great physics when you buy and use their game engine on all the platforms, but that you would need to buy a PPU for the PC.

It was mostly a reaction to the post by gurgi, and the general idea that a dedicated PPU will pwn a PS3, just because it's specially made for that and Sweeney might have meant that, if you look hard.

And totally on-topic.

The way i understand it, is that a PC CPU+PPU should give you some cool processing power to tackle physics calculations. However, i'm not totally sure how that compares to Cell, since they're just 2 completely different configurations. On Cell, everything is done on the same chip, there will be no bandwidth restrictions, which i think might potentially be a bottleneck on PCs, seen how the PPU has to get and send its data through slow PCI/PCIe buses (slow compared to the internal bandwidth in Cell).

Then on PC, everything needs to be also sent off to the graphics card. And let's not even start on the speed of the main Ram bus.

On PS3, this whole mess sounds much speedier, even if it turns out that a PPU might churn out more calculations than Cell. In the end, your system is only as fast as your slowest part.

Personally, i'd rather spend 300 quid on a PS3 than on a PPU on its own. The asking price is ridiculous, considering what it is.

 

[pc999]

The problem is that in PC, physics will not change the gameplay, but in consoles they probably( if devs want) will.

 

[Frank]

The way i understand it, is that a PC CPU+PPU should give you some cool processing power to tackle physics calculations. However, i'm not totally sure how that compares to Cell, since they're just 2 completely different configurations. On Cell, everything is done on the same chip, there will be no bandwidth restrictions, which i think might potentially be a bottleneck on PCs, seen how the PPU has to get and send its data through slow PCI/PCIe buses (slow compared to the internal bandwidth in Cell).

Then on PC, everything needs to be also sent off to the graphics card. And let's not even start on the speed of the main Ram bus.

On PS3, this whole mess sounds much speedier, even if it turns out that a PPU might churn out more calculations than Cell. In the end, your system is only as fast as your slowest part.

Personally, i'd rather spend 300 quid on a PS3 than on a PPU on its own. The asking price is ridiculous, considering what it is.

Yes, I totally agree.

And while Cell might be a bit more general purpose, the PPU has only half the transistors and runs slower, as it uses 130 nm. I think that evens it out nicely. A PCI(e) card with a Cell co-processor might be a much better bargain than one of those expensive PPU's.

 

[Frank]

The problem is that in PC, physics will not change the gameplay, but in consoles they probably( if devs want) will.

It might be different for single-user games. But you are right for multi-user ones.