Update statistic question

Thanks to all of those who have been answering my questions over the last few days !!! Its much appreciated !!! I have a question about the Update statistics script that we do here.... #### Beginning of script ##### set isolation dirty read; update statistics medium distributions only; update statistics high for table (Table name) (Column Name)distributions only; {We do the update statistics high on 13635 tables, like above} update statistics low;##### End of script ###### This was set up for me. I have worked out that the high over writes the mediums on the tables/ columns specified. It does an update low across the whole database. Does this mean that the lows have over written the highs ??? Should I change the order of this to low, med and then to the highs ?? Or to med, low and then the highs ?? My next stumbling block is the above script runs sequentially and takes over 2 days to complete. (we don't run it very often now) So that we can run this more often..... and maybe we will get better performance... What are my options in breaking up the above script ???? What do other folk do ??? Can I just break the highs script up and run several at once ??? Can split it up into table types... general ledger, accounts payable, sales etc and do the low, med and then the high on each table types ??? How many scripts I run at once ??? What is this dependant on ??? physical cpus ? cpu vps ?? Honestly, any help with this would be much appreciated, Thank in advance Best Regards Suze.