I certainly will let you know how it goes :-) The Xeons support significantly greater memory and bus bandwidth than the i5, so hopefully that will help to.
Maximum memory bandwidth 31,999.98 MB/s vs 25,600 MB/s Bus Data rate 46,928 MB/s vs 2,560 MB/s On Wed, Jan 6, 2016 at 1:13 PM Roman Lebedev <lebedev...@gmail.com> wrote: > On Wed, Jan 6, 2016 at 3:49 PM, Laurence Rochfort > <laurence.rochf...@gmail.com> wrote: > > Thanks all for the response. I'm getting some pretty huge numbers for a > 4x5 > > at 8000DPI using your formulas above. > > > > (4 * 8000) * (5 * 8000) = 1280000000 -> 1.2 Gigapixels? > Darktable should be able to handle such big images, but it was not > optimized in any > way for _that_ big images, so there might be a still bugs. Be sure to > use darktable-2.0 > I personally have tried loading ~350MPix images last year, it worked, but > slow. > > > 3 * 4 * 1280 * 4 = 61440 -> 61 GB RAM? > Yes, i think math is correct here... > > > Will it really need that much or will the tlinig you talk about reduce > that? > Well, no, that is the lower estimate, you can not* go below that number. > (* in darktable, because all the operations are working on 4-channel > floating point data, > and tiling is per-module, so we need to always have full-sized input > buffer and full-sized > output buffer + some internal memory for processing) > > (the alternative is per-pipe tiling, but it is not possible in > darktable. but you can "emulate" > it by splitting** that input 1.2 Gigapixels image into smaller pieces, > processing them separately, > and then joining** them. > ** outside of darktable) > > > Fortunately, I have access to 144GB of RAM so it doesn't really matter, > but > > just curious. > > > > > > Can I conclude that I'm unlikely to be CPU bound with a single 6 core/12 > > thread 2.4GHz Xeon? > I *think*, CPU <-> RAM connection will be the hotspot. > > Be sure to let us know if it works :) > > > Thanks for all the advice! > > > > On Wed, Jan 6, 2016 at 12:20 PM Roman Lebedev <lebedev...@gmail.com> > wrote: > >> > >> On Wed, Jan 6, 2016 at 3:08 PM, Michael Below <be...@judiz.de> wrote: > >> > To calculate MPix from DPI use (length_in_inch*nr_dpi) * > (width_in_inch > >> > * > >> > nr_dpi). > >> > > >> > So for 4” * 5” film at 3000 dpi you get (4 * 3000) * (5 * 3000) = 180 > >> > MPix > >> (yes, sounds about right) > >> > >> > According to Roman’s rule of thumb, one image will need > 8 GB RAM. > >> I should probably note that those 8Gb must not be the the total amount > of > >> RAM in the system, but the amount of free ram, fully available for > >> darktable. > >> > >> And do note that it is the lower estimate, in many cases darktable will > >> need > >> *much* more. Though in many of those cases tiling will kick in and help. > >> > >> > IMHO you don’t need to worry about CPU parallelism in that case, you > >> > should > >> > choose the slower CPU if you can avoid swapping that way. > >> > > >> > > >> > > >> > Cheers > >> > > >> > Michael > >> Roman. > >> > >> > > >> > > >> > > >> > Von: Laurence Rochfort [mailto:laurence.rochf...@gmail.com] > >> > Gesendet: Mittwoch, 6. Januar 2016 12:47 > >> > An: Roman Lebedev > >> > Cc: darktable-users@lists.sourceforge.net > >> > Betreff: Re: [Darktable-users] Benefit of more than 4 cores vs "speed" > >> > > >> > > >> > > >> > I have no idea how many MPix. I've only ever used film, so I don't > think > >> > of > >> > it in those terms. How can I calculate MPix from DPI? > >> > > >> > > >> > > >> > Any thoughts on CPU parallelism vs speed? > >> > > >> > > >> > > >> > Cheers, > >> > > >> > Laurence. > >> > > >> > > >> > > >> > On Wed, Jan 6, 2016 at 11:32 AM Roman Lebedev <lebedev...@gmail.com> > >> > wrote: > >> > > >> > On Wed, Jan 6, 2016 at 2:19 PM, Laurence Rochfort > >> > <laurence.rochf...@gmail.com> wrote: > >> >> Hello all, > >> > Hi. > >> > > >> >> > >> >> I'm building a new PC with scrounged components. I have the option of > >> >> either > >> >> a dual Xeon E5645 with up to 96GB RAM, or an i5-3470 with 8GB RAM. > >> >> > >> >> The storage is a PCIe x4 SSD. > >> >> > >> >> You can see a comparison here: > >> >> http://cpuboss.com/cpus/Intel-Xeon-E5645-vs-Intel-Core-i5-3470 > >> >> > >> >> I'll mostly be dealing with medium format and 4x5 drum scans, so TIFF > >> >> files > >> >> that are from 200MB to 1GB. Mostly I'll be doing crop, rotation, > colour > >> >> and > >> >> zone adjustment. > >> > Yes, but how much MPix? > >> > 50 MPix? 100 MPix? > >> > > >> > (very rough rule of thumb, lower estimate: for x pixel image, you want > >> > at least 3 * 4 * x * 4 bytes memory; that is, for 20MPix = 960 MB) > >> > > >> > If more than ~50MPix, then you *absolutely* need as much RAM as you > can > >> > get. > >> > I doubt that GPU would be of any help at those sizes though... > >> > > >> >> > >> >> Could people advise me on which would perform best? > >> >> > >> >> Many thanks, > >> >> Laurence. > >> > Roman. > >> > > >> >> > >> >> > >> >> > >> >> > ------------------------------------------------------------------------------ > >> >> > >> >> _______________________________________________ > >> >> Darktable-users mailing list > >> >> Darktable-users@lists.sourceforge.net > >> >> https://lists.sourceforge.net/lists/listinfo/darktable-users > >> >> > >> > > >> > > >> > > >> > > ------------------------------------------------------------------------------ > >> > > >> > _______________________________________________ > >> > Darktable-users mailing list > >> > Darktable-users@lists.sourceforge.net > >> > https://lists.sourceforge.net/lists/listinfo/darktable-users > >> > > >> > >> > >> > ------------------------------------------------------------------------------ > >> _______________________________________________ > >> Darktable-users mailing list > >> Darktable-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/darktable-users >
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