Problem with different nps with Arena and Little Blitzer

[jacobbl]

I have two versions of Sjakk 2.0 and 2d197. Both version as x32 and x64. On stand alone basis the x64 version have 50% higher nps than the x32 versions on both 2.0 and 2d197. The nps are nearly identical on 2.0 and 2d197. When I test the engines (x64) with Arena everything is working fine and I get the nps as I would expect. But when I test the engines with Little Blitzer the nps for 2d197 x64 isn't any faster than the x32 version, and 2.0 x64 is 50% faster than 2d197 x64. I find this very strange. Little Blitzer is using the UCI protocol, and Arena is using the winboard protocol, but I don't think this should matter.

Does anyone have any suggestions?

Regards
Jacob