Performance differences on a simple select on 2 tables using different SQL Server versions

Hi,

I'm experiencing a hugh performance difference between 3 SQLServer setups where the best/quickest machine has the worst performance. I'm out of ideas where to look.
I have a very simple database with 2 tables each containing 1 nvarchar(35) column with a unique non clustered index on that column.
Both tables contain roughly 850K unique entries, with some differences
I'm running the query:
select column1 from table1 where column1 not in (select column2 from table2)
(i'm aware that the SQL: select column1 from table1 where column1 not in (select column2 from table2 where column1=column2) performs a lot better, but that is not the point I'm investigating)
On a desktop, running SQL2000 8.00.2039 - Developer on a Windows XP OS with an intel duo processor, 1 GB Ram, this query takes 4 seconds
On a desktop, running SQL2005 9.00.4035.00 - Standard Edition on a Windows XP OS with intel duo processor, 2 GB Ram; this query takes 35 seconds
On a server, running SQL2005 64-bit 9.00.4035.00 (X64) - Developer on a Windows 2003 64bit OS with an Intel Xeon quad core processor, 16 GB Ram, this query takes more then 12 minutes!!
I've checked the execution plans and these are equal on all 3 machines (of course a table scan is performed in all the plans (rather then using the index) but that is not the issue I have to resolve).

All database properties between the 2 SQL2005 setups are compared and are equal. Text search/indexing etc. is disabled / removed

Can anyone point me in another direction as of where to look for this huge difference in performance? Is it as simple as Developer (2005) versus Standard (2005) ?

Thx for any indication!

How did you build the database (specially from SQL 2000 i guess) to two different SQL 2005 boxes?
Was it first created on SQL 2000 box and then restored on two different SQL 2005 boxes? If yes, there should not be any issue (keeping compatibility level). If you have created separately on each sql 2005 boxes and then transferred the data by some means.
You can apply some weired ideas
restart the SQL services/machine.
check locks on those tables
You can check on these lines as well.

Hi atulgoswami
Thanks for your reply
Only the slow machine (the 64 bit one) has been rebooted - as this is the one causing me the headache. Initially all databases for this simple test where created on each machine with an import of the data after that.
We have also tried restoring the SQL2005 database that takes 34 seconds onto the 64 bit machine, but no difference in the result.
We tried rebuilding indexes (although they are ignored), tried only importing the tables from a quick machine after creating an empty database. There are no locks. We only see a SPID for our query and a SPID on master and tempdb.

Which brings me to maybe an issue on tembd? I'll see if I can clean / rebuild this before aother test. I'll keep you posted. Thanks