TempDB issue(incresing file size issue)

Hi all,
I am having issue with tempdb . Initially i was having a 120gb drive and a four processor machine.
I have splitt the tempdb into 4 files intially with with default size of 14 gb with 10% unlimited growth. Then in next cycle increased the size of the file to 24 gb each.
Now the process has started taking more time and the process which was taking 2 hr 30 has gone to 29 hr.
i cannot figure out if some other setting is altered . Could anyone please suggest . It is urgent !!
Thanks in advance.
Abhishek

set the size of tempdb to be 30-40% of max size database.
it means if you database 10G , tempdb is 10 * 0.4 = 4 GB
create 4 datafiles , with 1GB each , and one log file with size 1 GB (log file with 25% of tempdb size) with auto 100MB.
if you can , distribute the datafiles over different physical disks (with different spindle)
Enabling Instant Data File Initialization , for speeding database creation / autogrow
can i know what the size of you database?

Hi ,
I am having a database of 55 GB size and the jobs use a lot of tempdb database in one job cycle it inserts 242 million records .
I had tempdb drive of 120 gb and i am not sure that is there any issue in allocating more size to the tempdb files?
Now we have split the tempdb files in 14 GB each .
Thanks
Abhishek