I'm still working in 10.0 and I've always had this problem. I too regularly geocode 90,000 students from excel files. It turns out what was happening was the goecoding process reads each field in the excel file as 250 characters wide. This was creating huge files that most often would crash partway through.
The solution that worked for me was to convert the excel file to an info table, defining each field with appropriate field widths.
Then geocode the info table.
More specifically;
open arcToolbox,
select Conversion Tools,
select To Geodatabase,
select Table to Table.
When the wizard opens, under Field Map, right click on each field and define the properties. With large files this process can take quite awhile.
Hope this helps.
Patricia