Probably. But it's too early to tell - we're still a year away from RTM for
VS.NET 2005 and the 2.0 framework - and performance tuning work frequently
is saved for the end of the development cycle.
I'd speculate that it's unlikely that 2005 languages will be dramatically
faster, but I know, for example, that in native (not managed) C++, the
compiler does have significant new optimization technology that can result
in gains of 30% (10% is more typical).