|Yes the original cable has a circular device (ferrite bead).|
1) It looks just like this:
2) Also my extension cable looks like this, just as you described:
Cable "1" works flawlessly on both operating system. Cable "2" the "extension" does not work on Windows 7.
As mentioned before, the "Cable 2" does work perfectly on Ubuntu, just not on Win7. It acts like it needs a driver, but this should not be the case.