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iMac with GTX 680MX for 4k Dailies
We’re waiting to upgrade our Mac Pro towers and are looking for an interim machine for creating 1080 dailies from various 4k and 2k source (XAVC, Sony RAW, Phantom Cine, etc). Does anyone know if the current 27″ iMac with GTX 680MX GPU would be a reasonable choice for managing this? We’re hoping to achieve at least 12 fps transcoding to make it worthwhile.
Also, while we don’t envision employing the imac as a dedicated grading station, would it be unreasonable to think that we could add additional GPU to improve performance if we’re interested in running Resolve (occasionally) in this capacity?
Thanks in advance,
Eric -
5 Replies
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[Eric Liner] “would it be unreasonable to think that we could add additional GPU to improve performance “
Performance is a blend of data-throughput and total CUDA-core processing. If you can string out a farm of graphics processors, then there is little to prohibit going ahead. What is guaranteed is published in the Blackmagic Resolve configuration guide, for Mac and Windows platforms, towers, laptops and i-devices.
This mostly only applies to the licensed version.
jPo
“I always pass on free advice — its never of any use to me” Oscar Wilde.
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You would probably have to test it, I know people are getting decent performance from the latest iMac’s but the smaller amount of VRAM might cause some performance hit with 4K material.
Keep in mind that Apple does not support GPUs over Thunderbolt so you are stuck with that GPU and that GPU only.
-Rob-
Robert Houllahan
Director / Colorist
Cinelab Inc.
http://www.cinelab.comMAHC-PRO 6-Core 2X GTX580 20Tb SAS Wave Panel Panny 11UK SDI Plasma. Light-Space CMS + Hubble
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On an MBP i7 non-retina with a GTX750 we’ve seen over 36 fps for Alexa ProRes to DNxHD, about 20-25 fps for ArriRAW, and nearly that much for F65 RAW. So the GTX680 in an iMac will do the same or better.
For ArriRAW and F65RAW, the read speed of the disk holding the cam orig files also matters. Rreading from one drive, writing to another improves render speed. Reading writing simultaneously to a RAID5 can drop render speed at times.
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Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India -
Thanks guys,
This is all very helpful. I hadn’t realized that thunderbolt didn’t support GPU. No other I/O options on MBP or iMac for GPU expansion, huh?
Thanks again,
Eric
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On this I am interested to know will Davinci use CUDA if there is only one GPU present, presuming it is a CUDA enabled processor. Also, given that on an IMAC you are running an ULTRASTUDIO pro off one THUNDERBOLT port I am wondering if you are better off using USB 3 for your harddrives (up to 5Gbs) rather than share the THUNDERBOLT – I am not certain that the two thunderbolt ports are really two totally separate THUNDERBOLT connections?
Any thoughts?
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