Slow Attribute Edits

Hi,

When I have a lot of blocks defined in a drawing, editing the attribute values in a block becomes slow. Each time I change a value and hit enter there is quite a lag before the next attribute in the list can be edited. This lag is not present when there are only a few blocks defined. Can anyone explain where the overhead comes in when there are a lot of blocks defined and whether it can be alleviated in any way?

My PC is not very fast, but is perfectly OK for most CAD tasks that I carry out.

Thanks

Jamie