Performance issue with Linq Queries

We are using Typemock Isolator 5.3.1 and the newest NUnit version with VS2008 SP1.

We are using linq in a large C# project (bad decision but can't change it anymore) and some of our queries are very big (>100 code lines). We have unit tests and there is a significant performance issue when such a query gets executed as linq parses the whole thing in order to create the sql statement. This of course is a linq issue and not a typemock problem.

But typemock seems to have some impact on the performance as well. When running a test that executes said query it takes about 17s to run. When I disable typemock (VS2008 Menu -> Tools) and execute the test again it takes only 6s. It seems to me that the parsing by linq gets affected by some typemock functionality what results in an even longer execution time. As we have a number of such tests solving 10s on every one of them would reduce our build time by about 10min!

Is this a bug that you can fix? Is there a workaround? Or can I at least disable/shutdown typemock for some specific tests?