Alternative to the default bioformat tif saving: simply convert the image to ImageJ and use the faster IJ saving. Save the metadata in the icy xml.
Select the sequence you want to save, and the destination file, which should end with .tif. If you enter a file name without .tif extension, it will be added.
Pros: faster (really)
Cons: needs twice as memory (due to the conversion to ImagePlus) .