I rarely use them, but you might try creating a Block of your sketch and hatch, then place the block where needed instead of creating the multiple hatches. I don't know for sure if it will work, but no one else has replied, and it's worth a shot.
Glenn, thanks for the idea. I haven't attempted this feat with a block yet. I don't use blocks very much. I imagine this will involve clicking every location where the block is needed unless there is an array function that could be used.
For fun I tried applying the solid hatch at the sketch level in the model. When I began performance was fine. However, as I created more and more hatched circles the computer quickly slowed. I exported the sketch hatch file to pdf and the quality wasn't as nice as the pdf exported from the drawing hatch file. For whatever reason the filled in circles from the sketch hatch file attempt looked a bit like Pac-Man. Not sure why that happened.
If I understand you correctly you are filling in each circle solid black? My approach would be to save the drawing without any fills to pdf, or dxf, then open in a vector editing program such as InkScape which is free. Then in inkscape you'd be able to select all of the circles and change them all to filled at once. Then you can save back out to pdf. Or if you think it would be easy in Autocad you could do the same thing there (or in Draftsight which is free) with a dxf.
I just did a quick test and for importing circles into InkScape and I think dxf format works better than pdf.