Here gmic_gimp for Win64.
The command line tool is too big to post here (max 5MB)
I don't know, whether it works, for me it seems to work perfectly but I din't check all filters :-)

Hmm that crashes for me on loading gimp... perhaps it needs different .dll versions from the one I have?

http://www.aljacom.com/~gmic/
(gmic-beta_full_64bits_win.zip)

samj! Can you please tell me how you do this? It would be really great to know the build setup... if you could take the time to tell me I'll put it on the gmic wiki.

*Edit* I see you have some pages in French, I will try to read them!

@garagecoder:
I don't know. Without error message, it is hard to say.

OK with the dlls samj version includes, onkel your version also works. Can you tell me the build environment?

By the way, thankyou samj!

@Garagecoder

Do not translate my documents, there are old.
The compilation is the same as it is on Linux.
For a compilation method you can visit the website of Partha.
The list of libraries is in the file "makefile".
To compile G'MIC: make windows
To compile Gimp plugin: make gimp

It is Mingw64 with Vista 64. Hmm, what other infos of my build environment do you want to know?
I think gcc version is 4.6.1, but I made some experiments with gcc 4.8.0, but there are too much differences...
I made some more optimizations, so maybe, my build is a little tickle faster than Samjs, but maybe less accurate, I don't
know.

I will receive soon a new laptop with a 64bits CPU and Windows8, I'll try to set up the environment to build the plug-in (as I did on Win32).

Ah this is good news

Thanks Onkel I will try this out at some point so I can update the wiki

@Onkel Hatti

Your compilation works on my 64-bit version of Gimp 2.8 Sourceforge
After a few tests the speeds are the same.

@Garagecoder

I use mingw64 - GCC 4.7.2

OK thanks Onkel and samj

Does anyone know what happened to the "custom code" filters under various? I don't seem to have it now

edit: Wait, it's there in Onkel's version! samj I think some of the filters are missing in yours, it's as if it has only the default stuff...

How strange is that ! How many filters do you have GC ? (I've 475 filters available with the default install).

Yes it's fine now, I use the dlls from samj but the exe from Onkel

@Garagecoder

The version is 1.5.6.1 beta with 475 filters.

When I use your exe samj, I have 205 filters. It does say 1.5.6.1 (beta) at the top, but the update function seems to be the old method - it tries to download the individual source filter files. When I copy in Onkel's exe I then have 489 (because of some test filters of my own).

edit: I've also just noticed odd behaviour with the progress bar (in both versions), now when I run a filter the bar goes instantly to 100% and sticks there until complete. I even updated gimp to 2.8.4 just to be sure and it's the same.

@Garagecoder

I don't doubt that you are seeing 475, what I suspect is your version is picking them up from older .gmic filter files! Still not sure what's going on with the progress bar either

Sorry I just seem to be a troublemaker these days