Emergency! Performance downloading big files

This is a holiday-crunch emergency. I'm dealing with a client from whom we need to download many large PDF docs 24x7, several thousand per hour, all between a few hundred K and about 50 MB. Their security process requires the files to be downloaded via https using a big long URL with lots of credential parameters. Here's how I'm doing it. This is on Windows, a quad Xeon with 16GB RAM: $ctx = stream_context_create(array('http' => array('timeout' => 1200))); $contents = file_get_contents($full_url, 0, $ctx); $fp = fopen('D:\\DocShare\\'.$filename, "w"); $bytes_written = fwrite($fp, $contents); fclose($fp); It's WAY TOO SLOW. I can paste the URL into a browser and download even the largest files quite quickly, but the PHP method bottlenecks and cannot keep up. Is there a SUBSTANTIALLY faster way to download and save these files? Keep in mind the client's requirements cannot be changed. Thanks for any suggestions.