I have tried to performance tune SQL Server 2005 database to unfortunately try and take a hit of absurd queries generated by the client and LINQ to SQL. But it apperently hasnt made any difference in terms of performance improvement.

it did state it would improve performance by about 77% - but supposidly there isnt much of a difference

so, anything else I can do to improve the SQL performance?

LINQ generates an unreal query unfortunately to do a search on multiple tables. This causes the whole thing to slow down of course but we cannot change LINQ, whilst there are plans to make a DAL from scratch in the ASP.NET application, until then we cannot do much.