[Qgis-user] QGis and Mac hardware

[Even Rouault]

Le lundi 07 novembre 2016 19:18:33, Nicolas Cadieux a écrit :
> Hi,
> 
> Currently GPU acceleration is not used.  Maybe some plugins can use it but
> I have not seen anything yet.  I have put in a request to use GPU for the
> qgis 3.0 raster calculator as it needs to be upgraded for huge rasters. 
> Currently , the qgis raster calculator can not handle big rasters.  The
> new version needs to break up the raster into smaller chucks and if you
> have done that, you might as well use the multi CPU ou GPU to do the rest.
>  I an hopping this will be fixed for 3.0.  Rendering is multithreaded and
> will be faster the more cores you have.  Personally, I would go for the
> quad core without even thinking for this and other softwares.  I would
> think of getting an ssd also.  I have not used qgis on a MAC (PC and
> ubuntu only) but I expect this comment  to be valid for Macs also.

If you use gdalwarp, with GDAL configured with OpenCL (which is rarely the case 
for most standard binary builds), you can get GPU acceleration for non nearest 
neighbour resampling. Although currently the gain is generally modest (or even 
slower) w.r.t multi-threaded acceleration, and you may face issues with buggy 
OpenCL drivers. Might be that the OpenCL code path isn't completely optimized 
too as it is still rather experimental.

> 
> Nicolas
> 
> > Le 7 nov. 2016 à 11:12, Matthias Kuhn-2 [via OSGeo.org]
> > <ml-node+s1560n5294662h83 at n6.nabble.com> a écrit :
> > 
> > Hi
> > 
> > On 11/07/2016 05:02 PM, Square Cube wrote:
> > >> I am looking to update some hardware and am trying to evaluate what
> > >> performance difference in QGis might be gained from the options
> > >> currently on offer from Apple.  I have two specific questions:
> > >> 
> > >> - Does QGis have GPU acceleration features that leave the graphics
> > >> card to perform certain calculations, instead of the CPU?
> > 
> > No
> > 
> > >> - Does QGis take advantage of multiple cores and / or multithreaded
> > >> rendering?
> > 
> > Yes, and it is expected that it will make even more use of multiple
> > cores in the upcoming QGIS 3.0 version.
> > 
> > Matthias
> > 
> > >> I am trying to understand if it would be worth my while investing in a
> > >> 15" MacBookPro (with quad core CPU and discreet graphics card) over a
> > >> 13" MacBook Pro (with dual core CPU and integrated graphics).
> > >> 
> > >> Very grateful for any advice.
> > > 
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