P2 Speed Tests

[ullanta]

Hi Folks! All this talk about benefits - now, in the future, theoretical - of P2's 640Mbps transfer speed has led me to want to investigate the speed a bit.

My first test was simple - duplicating a 1.8 GB "contents" folder on P2 card plugged into a Mac G4 laptop. I was surprised to find that the operation was slower than duping it to a hard drive. I would have expected a pure P2 to P2 transfer to be a lot faster; the Cardbus bandwidth should not impose a limitation.

Using a Mac, I can't play multiple streams directly off the card right now (though I'l try importing 'em, then copying the QTs onto the card for testing later).

In the meantime, I'd like to ask people (especially people with PC laptops) to do some testing. A simple P2 to P2 dupe, as above, would be an interesting comparison. If anyone has a 2-slot laptop, copying speed from one P2 card to another would be interesting as well. Finally, I know the Green Barry has discussed this in theory, but I don't remember if he did any hard testing of running multiple streams off a single P2 card simultaneously in an NLE - anyone care to push that limit?

I'm hoping all this will give some real-world info on P2 capabilities, and also perhaps help diagnose some of the Mac issues.

I suppose any of the standard drive-speed testing utilities would be interesting and clearer for comparison, as well, if anyone has those installed...

 

[THoff]

My results on a P4M 1.5GHz Toshiba laptop running Windows XP Home

Hitachi 7200RPM internal PATA Drive

8GB P2 Card in PCMCIA/PCCard Slot

Random access is much faster on the P2 card, but the internal drive has a higher sustained sequential read speed. Unfortunately this program doesn't test write speeds.

 

[Barry_Green]

I've run four streams of 1080 footage off a card simultaneously in EDIUS, no dropped frames. I'm sure it could handle six, and if I had a quad-core processor system I don't doubt that it could handle 15 streams of 720/24pN.

 

[ullanta]

Interesting - THoff gets a surprisingly low read speed (27MB/s); Green Barry's talking 400Mbps (50MB/s).

Barry, you've mentioned a more complex functionality for a P2 card than a general storage device. Do you have any idea if Edius might be taking advantage of functionality a general drive-tester doesn't know about?

 

[THoff]

I don't think what I'm seeing contradicts Barry's experience at all. The fact that the P2 card has extremely fast random access speeds (a magnitutde faster than the 7200RPM drive) due to a complete lack of moving parts actually helps it with multiple streams.

On my system the P2 card provides enough bandwidth for at least three streams of 720/24PN, and while the Hitachi hard drive has higher throughput on sequential reads, I doubt that it could handle the seeks it will have to perform to read from three different disk locations.

 

[ullanta]

Right; clearly the access speed makes a tremendous difference. But the sustained speed should be much faster. I for one have been surprised by slow transfer speeds of the entire contents of the card, which involves transfer of large files sequentially. Firther, a lot of ther debate of P2 vs. other solid-state keeps going back to P2's 640Mbps... and the fact that P2 is not the bottleneck in speed... but in your tests, it seems to be, at least for large transfers.