I fix this on my own servers by combining AJAX calls. Performance improvement is quite drastic if there are a large number of records. It also depends on how much latency there is between you and the server.
Here are my install notes for anyone that might be interested. It should just be cut & paste and you can easily enabled/disable this by changing one line.
There are two other simple speed improvements explained in that document. Combining AJAX calls makes the biggest difference though.