Slow file drag: is there a fix?

Hi everyone, I'm new to this forum, but use Macs since 2008. I recently updated from OSX Snow Leopard to Lion, and dragging files became unbearably slow. I always moved large files and folders with several files without any problems in SL, but in Lion this is really painful. Just to make it clear, I'm doing things the same way I always did; the only thing that changed is the OS. File dragging became slow in all situations, including from folder to folder, and from my Mac to an external HDD (both via firewire and USB). Why did file dragging become so slow? Is there a fix to this bug? Thank you very much.