In practice? No, not in release versions - the intermediate variable will be optimised out.
In debug versions there is likely to be a difference as debug versions generally do not employ as aggressive optimisations, if it uses any at all.
You can check for yourself: this explains how to view the IL
http://www.ginktage.com/2011/04/display-il-code-in-visual-studio-2010/[
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But...having said that most of the optimisation is done at the JIT compiler which uses the IL as the input, and doesn't really care if you are debugging or not...
http://blogs.msdn.com/b/ericlippert/archive/2009/06/11/what-does-the-optimize-switch-do.aspx[
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It's complicated: Personally I would use the first version because it is easier to read, and to debug - but in practice it will make no difference at all! :laugh: