...is there a reason you're downloading "All" patches, instead of just the current ones? I made the same mistake when we set up Patch Managemetn for the first time; there's no need to download patches which are superseded.
The easiest way to do this is to load the Manage Software Updates tool, and set the "Show" drop-down to "Superseded Bulletin Summary", and set the "Supersedence Status" to "Superseded". When the report refreshes, right-click on any Bulletin which is shown and select "Disable". You can multi-select (via Shift-click or drag-selecting) and disable them all at once.
Also..it could be you've hit a particularly "big" patch. There were some earlier this year (or last year?) that were several hundred MB. I think they were Visual Studio patches or something.<o p=""></o>