i5 (4core) better than xeon e5 2407 (8core)
 

hi guys, in order to be more faster in my cfd simulation i bought a server hp pro liant gen 8 with 2 xenon e5 2407 processor (8core) and 64 gb ram (balanced). my simulation always do not exceed 4*10^6 cell on mesh (academic use).
can you explain me why my hp pc with i5 with 4 core is much faster than pro liant?
i use openfoam to do my simulation and regarding the processor datasheet it seems similar but in reality not. could anyone explain me why or what ican do to solve this problem?
thanks.

You will have to be more specific.
"hp pc with I5 4 core" could be anything. Which generation? Which exact CPU type? Memory type and population? How much faster is it exactly in single- and multicore?
Apart from that, a Xeon E5 2407 really is not your first choice for a CFD processor.
It is a pretty old architecture, has a low clock speed, only three memory channels and support for DDR3-1066 maximum. There are better options for about the same budget. Plus with 64GB of RAM and 6 memory channels in total there is a high chance your memory is not populated properly.