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Author Topic: How bandwidth intensive (PCIe) is Photoscan?  (Read 5968 times)

Marcel

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How bandwidth intensive (PCIe) is Photoscan?
« on: November 19, 2013, 08:57:03 PM »
How bandwidth intensive is Photoscan? Bitcoin miners aren't very bandwidth intensive for example, you can plug a graphics card in a PCI 1x slot and the performance would be similar to a card in a PCI 16x slot (because the card spends most it's time crunching numbers, and doesn't send/receive much data).

Is this the same with Photoscan? Could I use an extra graphics card in a PCI 1x slot, or would this card have low performance?

Wishgranter

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Re: How bandwidth intensive (PCIe) is Photoscan?
« Reply #1 on: November 19, 2013, 09:46:17 PM »
If its PCI 3.0 then 1x slot will be enough.... how much and what cards you have already in system ?
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Marcel

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Re: How bandwidth intensive (PCIe) is Photoscan?
« Reply #2 on: November 19, 2013, 10:14:23 PM »
Thanks, that's promising!

This is still hypothetically speaking. I was looking at the crazy Bitcoin mining rigs with 6x AMD 7950 cards, and I just wondered if that would work for Photoscan as well :)

kels

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Re: How bandwidth intensive (PCIe) is Photoscan?
« Reply #3 on: November 19, 2013, 10:54:21 PM »
nothing to do w/ Photoscan but ASIC outperforms any 7950 by a factor of 1000 ---> 600GH/s
https://en.bitcoin.it/wiki/Mining_hardware_comparison
http://www.butterflylabs.com/



Wishgranter

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Re: How bandwidth intensive (PCIe) is Photoscan?
« Reply #4 on: November 19, 2013, 11:21:52 PM »
heheh, yes thats right. but the BITCOIN is not the only one. some of them are for GPUS still and cannot be "harvested" with ASIC... when im not  ended mining from 2009 then now i would have approx 190 BTCs, my fiend used just the CPU for that and have already 160 BTCs....

But will say, its mostly enought with the 2-3x  7970 cards for the AGI solution. only if you want process 100s of images on medium-high or ULTRA .....
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Marcel

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Re: How bandwidth intensive (PCIe) is Photoscan?
« Reply #5 on: December 14, 2013, 12:18:27 AM »
I got my hands on a 1x Pci riser, so I decided to put this to the test by connecting my second GPU through the riser card.

This is with the benchmark project:
Code: [Select]
Device 1 performance: 857.128 million samples/sec (Hawaii)
Device 2 performance: 626.932 million samples/sec (Hawaii)
Total performance: 1484.06 million samples/sec

This is a project with 21MP images:
Code: [Select]
Device 1 performance: 742.359 million samples/sec (Hawaii)
Device 2 performance: 549.72 million samples/sec (Hawaii)
Total performance: 1292.08 million samples/sec

Normally the values are pretty even, so it's clear that running a GPU over PCI 1x connection has a performance penalty (even if it's a PCI gen 3.0 port) If you'd need to use risers then getting PCI 16x versions would be the best.

That said, adding more than 2 GPUs doesn't make much sense as long the depth map filtering phase of the Dense Cloud is not GPU accelerated. Better to have multiple machines with 2 GPUs each.