Poor performance of XML parsing

Poor performance of XML parsing

I pull XML from server using .load() and then iterate with .each() over some 3000 nodes. I use .find() to get 7 sub-nodes and store them internally (into arrays). It works, but it is disappointingly slow. On my obsolete P4 it can take 8-10 seconds during which the whole browser (FF) is completely frozen. On faster computers the processing time is shorter, but still way too long. What can I do to cut this time? I certainly need speed up of an order, two orders would be nice. Would JSON be any faster? Or should I pull text/plain in custom format and parse it in my JS code? I am not very experienced, so I don't know what the options are.

Thanks for any help,
Borek