...but I believed that 8120 had potential to shine when new windows comes out... while Intel was already out of juice...
I wouldn't quite say that Intel was out of juice.
Sure, the 8120 may perform better on Windows8, but then the 2500k may perform just as well, if not better.
The fact is that right now, i2500k is better, plain and simple. To buy in the hope that in the future...maybe.... if MS decide to program their new OS properly and optimise is for BD architecture...maybe...AMD BD will perform better than i2500k, is not logical thinking. It is far more likely that Win8 will perform better with a i2500k powering it than a 8120.
It has been shown that Win8 performance should should roughly a 10% improvement (compared with Win7), for BD, however, is this enough for it to be able to overtake the i2500k? I don't think it is.
When you consider that i2500k overclocks like a demon, the BD is left dead in the water.
The only time that BD becomes a genuinely viable choice is if it is vastly cheaper than the i2500k and if the user will not be overclocking....and if you are buying a i2500k, then you are almost certainly going to be overclocking, otherwise you would just buy the i2500.
In any case, the first gen BD seems bad. I'm sure that a BD2 will be released and a lot of the bugs will be worked out and this should offer something more competitive. I actually think that AMD are on the right track. It just so happens that their first gen BD is up against the best commercially available CPU ever produced (ie. the i2500k/i2600k).