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pci express question.

Posted: Mon May 03, 2010 5:28 pm
by juan
Hi im about to buy a new system and im wondering if the pci express badwith (or speed i dont know) affects the rendering speed. ( i want a Mother board that supports 3 or 4 graphics cards, but the bandwith of each pci express port is different (you know like: 2pci express 16x and 1 pcie xpress 8 )



theese are the options:

http://www.newegg.com/Product/Product.a ... 6813131358

http://www.newegg.com/Product/Product.a ... %20Extreme

http://www.newegg.com/Product/Product.a ... sus%20P6T7


thanks. :mrgreen:

and this is an octaner dream ;) : http://hardforum.com/showthread.php?t=1 ... trexer+sli

Re: pci express question.

Posted: Mon May 03, 2010 6:50 pm
by Proupin
juan wrote: and this is an octaner dream ;) : http://hardforum.com/showthread.php?t=1 ... trexer+sli
hahaha, I loved the fire-fighter collage :lol:

Re: pci express question.

Posted: Mon May 03, 2010 7:11 pm
by juan
jaja indeed

Re: pci express question.

Posted: Tue May 04, 2010 8:47 am
by radiance
16x is perfect, 8x is doable, 4x is too slow.

that's the rule :)

Radiance

Re: pci express question.

Posted: Tue May 04, 2010 3:41 pm
by juan
thanks Randiance

Re: pci express question.

Posted: Tue May 11, 2010 1:27 am
by scandog72
I have just purchased a GTX 260 and installed it in my older mother board with PCI Express 1.1, and am getting okay results faster than my 9600GT.

Would it render any faster with PCI Express 2.0? I can't really afford to upgrade to the latest and greatest, and it is not worth it to spending money on a 775 motherboard any more with so much fast out.

I know the bandwidth is supposed to be twice as fast but not sure if that would affect Octane or just games.

Thanks,

Re: pci express question.

Posted: Tue May 11, 2010 3:12 am
by jipe
What kind of Megasamples are you getting on the benchmark test scene (the trench with daylight)? I get 1.49Ms/s with my GTX 260 (PCI-E 2.0 x16 slot) and I know others get better performance depending on their particular card & model.

Re: pci express question.

Posted: Tue May 11, 2010 4:04 am
by scandog72
I was getting 1.52Ms/s and it rendered in 24-25min at 4000 samples.

So I guess getting PCI express 2.0 won't gain anything for Octane.

It's a super clocked at 626Mhz, I suppose it might be a bit faster with faster bus.

Re: pci express question.

Posted: Wed May 12, 2010 5:36 pm
by havensole
There are a few boards out there that will support 3-4 pcie cards at full 16x, but they are pretty darn expensive. Then you will need a case that can support the 3-4 double wide cards, if that is the route you are going.

Re: pci express question.

Posted: Wed May 12, 2010 5:48 pm
by radiance
Octane only transfers large amounts of data once you click on the meshnode,
after that it only sends small commands and little bits of data, so the pci-bus speed is not that important.

it will even work on a 1x speed, but it might take 2-3 minutes to load the model into your GPU on the first click and you will get some lag when changing material nodes/params.

once it's in the gpu there really is'nt much traffic over the PCI-E bus.

Radiance