Why not have a USB/FW PPU?

D

Dew

2[H]4U
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I posted this in a thread earlier, but as it was on the third page, it got no responses:

Here is a thought. Why PCI/PCIe? Why not FW/USB2? Transfers after level load will be minimal. Latency?

The biggest bitch I see here [IRT PhysX] is no one having room for a card, can that issue be eliminated?
 
Off the top of my head:

Not enough bandwidth, don't confuse mega-bits per second with mega-bytes per second.

The card would also have to be packaged in an external enclosure adding to production costs. As well as an AC adaptor for power since FireWire & USB2 won't be able to feed it enough power.

Less people have FireWire/USB2 then a PCI slot.

The issue of available PCI(e) slots is more of a problem for anyone running SLI/Crossfire, if the PPU takes off i'm sure mobo manufacturers will take this into account.
 
Nowhere near enough bandwidth or speed. Thats like saying "why arent there external high-end gaming cards?", its just not possible due to the speed calculations are made and need to be sent at. The cards need a more direct route to the computers architecture and also need to operate on a physical level, not software which is what USB or Firewire would entail.

Its all basically about latency. Software is slow, hardware is fast.
 
way too slow

I'm sure instances of people not having enough slots will be rather rare.
 
USB2/FW will do 40-50Mbytes/sec, so I don't see how bandwidth can be an issue since the main argument for PCI is that all the processed data is a few megabytes a second at most. Considering the PCI bus peaks at 133MB/sec (theoretical), how is an interface which is almost half the speed make a bandwidth difference?

Which brings us back to the question of latency.
 
I say make SATA 5 1/2 inch bay PPUs, think about it: SATA does 3Gbits/Second.....I don't think a PPU even needs that speed, plus: Who DOESN'T have a 5 1/2 inch slot? I think the 5 1/2 inch should be a seperate product, there still needs to be a PCI version.
 
*pushes up glasses w finger*
*snorts like Urkel*

Well to be correct, it's a 5.25 (5 1/4 inches).

If the PPU takes off, they need to hop to and get a PCIe card out there. I only have 2 PCI slots, and they are currently occupied. I do have free PCIe slots however, so it'd be nice to see companies start making cards for them that aren't video cards.
 
USB and SATA people are missing the point. It doesnt matter if USB or SATA could carry 10000000gb/s, they're all too slow in terms of latency. SATA may have 3gb/s but thats a sustained single read or write, not thousands or millions of different streams a second(which is what the PPU will be doin).

PCI has quicker access time to the core hardware compared to USB(which is slow because it relys on software) and SATA(which relys on a controller).
 
SATA is for disk access, it wouldn't matter if you could send data up and down the cable at 50x10^24 MB /sec, because the SATA controller would be holding up the show.

and a PPU will need a shitload of bus speed, personally, I don't even think the PCI or PCI-E bus will be fast enough to support what is being claimed from these things.

Lo Pan said:
I say make SATA 5 1/2 inch bay PPUs, think about it: SATA does 3Gbits/Second.....I don't think a PPU even needs that speed, plus: Who DOESN'T have a 5 1/2 inch slot? I think the 5 1/2 inch should be a seperate product, there still needs to be a PCI version.
Click to expand...
 
Negative zomg. All the PPU needs to do is run results out and calculations in. The results wouldn't be thousands of seperate streams, I think it would (should) be about 10 streams for seperate kinds of physics calculation. One for motion, trajectory, force, and momentum.
 
Lo Pan said:
Negative zomg. All the PPU needs to do is run results out and calculations in. The results wouldn't be thousands of seperate streams, I think it would (should) be about 10 streams for seperate kinds of physics calculation. One for motion, trajectory, force, and momentum.
Click to expand...
'Streams' was just used for explinations sake but your right in the sense that the PPU doesnt do lots of different things at once, it does tonnes of things one after the other.

Just replace 'Streams' with the word 'Processes' and it sounds better :)
 
Lo Pan said:
Negative zomg. All the PPU needs to do is run results out and calculations in. The results wouldn't be thousands of seperate streams, I think it would (should) be about 10 streams for seperate kinds of physics calculation. One for motion, trajectory, force, and momentum.
Click to expand...
When its doing these calculations for hundreds of thousands of objects simultaneously, latency is killer, especially if the objects effect game play.
 
ok their is a lot of bullcrap in this thread.
A PPU WILL need a lot of bandwidth. Remember that this is a specialized processors. Processors needs a lot of bandwidth. Saying "it just takes data as an input, and sends the results back" does not mean that it won't take a lot of bandwidth. If you don't believe me, explain me how is that quote different from what a CPU does. And saying that sata would be faster is also a whole lot wrong, because everything that goes trought sata must still go throught a bus like PCI before it reaches the sata controller, which is why using sata has an higher latency than the pci bus. Also, sata is for storage.
Anyway, what I meant is, wait for the pcie version of the PPU. I won't ever buy a PPU if it does not have a pcie interface. Just like I won't ever buy a gadget like the i-ram if it does not come with a sas interface.

Also, I find it weird that people say that the interface speed is not important when it is the case, while they will do the opposite when it's not the case, like saying that sata300 drives are better than sata150 drives.
 
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