You are right...I wasn't trying to be snarky. I was genuinely confused as to if you were being serious or were joking. The emoticon also added to my confusion as to if you were serious or not. No disrespect intended.
As for memory leaks in XP with Railworks? I haven't used XP in years and have only used Railworks in Win 7 & 8.1 so I don't know how the memory leaks manifest themselves. Maybe their better memory management has shielded me from witnessing the effects of leaks in this sim.
As for getting an OEM copy of Win 7 and the decision on whether to upgrade to 10? I say upgrade to 10 and if you don't like it, revert back to using 7. The other option is to have a dual boot arrangement and have 7 & 10 on their own partitions if allowed.
My hunch is that 10's memory management will likely not be much different than 8.1's. Maybe a few tweaks that we will not notice in comparisons with 8.1 performance-wise. I know boot up, shut down and especially entering and exiting sleep mode is faster in 8.1 than it is in 7. But my guess is (other than DX12), we won't see much of a difference in 10 over 8.1 from a performance angle. I could be wrong, but MS certainly haven't been hyping that aspect beyond DX12, so I suspect it's because they aren't really a factor.
Win 10 from what I'm reading is more interface tweaks, a new browser called "Spartan", ....better integration with the following.....mobile Windows (universal apps), OneDrive cloud, Xbox One, the mobile OS's "Cortana" voice/search features (similar to Apple's Siri) in the desktop/laptop realm now and with the new holographic headset.