Users of the newly released Remote Desktop Manager 9.0 will notice that there's now a 64-bit version installed alongside the 32-bit version. Upon running this 64-bit version, you'll notice how much slower it is than the 32-bit version. I posted it on the Devolutions forum and got this reply, designating it as a known issue with 64-bit .NET.

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Hi,
Unfortunately this is known issue with .NET 64.

http://stackoverflow.com/questions/12979774/net-4-0-app-slower-on-64-bit-than-32-bit-profiling-and-possible-solutions-ap

By the way we recommend to use the 32 bit version of RDM ans switch to the 64 version only if you get some memory limitation. We have more technology integrated and it's faster.

I know that the next .NET update should fix this issue