Why do you think the performance would be different? You would first need to know what dbo means in this context. Have a look here:
http://msdn.microsoft.com/en-us/library/aa905208%28v=sql.80%29.aspx[
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If you care about good coding and also about performance you might take another look at "select *". You should explicitly select the fields you want, something like "select A, B, C from table ...". This way you're sure you get the fields the way you want them (because no assumptions can be made on the defined field order of your table). Also, you get better performance by specifying only the fields needed and therefor don't retrieve data from fields you do not need.
Good luck!