Windows server 2008 vs 2012

As window server 2012 is powerful and have to handle less connection, but it is much slower than window server 2008.Probably the problem is inside our .exe (even if its the same for both the machines) but we're thinking that the problem can be Windows 2012 too. Does any one have idea about the what is the difference of this purpose? Kindly help me, I will be thankful to you.
