On Wed, Jan 6, 2016 at 2:46 PM, Laurence Rochfort <laurence.rochf...@gmail.com> wrote: > 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? Well, no clue, i do not scan, but i guess math is something like: Scan area dimensions, in inch; multiplied by DPI (which is dots per inch) will give you dimensions of scanned image, in pixels. Now, multiply those, and you should have pixel count.
> > Any thoughts on CPU parallelism vs speed? All operation in darktable are using OpenMP, so all cores will be used. (second cpu, on the other hand, i **think** will not be used) > > Cheers, > Laurence. Roman. > > 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
