We really have no way of knowing so people should stop making these threads. Also, typically in games there is very little difference in performance when you overclock your CPU. I ran Crysis benchmarking tool and only got 2 more FPS average with my CPU @ 4GHz then I did with it @ 2.66GHz.
There is actually plenty to go on.
1-Skyrim will be on the 360 and PS3. There is no console game an average gaming PC can't run.
2-Your test of Crysis should tell you the role of the CPU is limited. If you think your Crysis bench is odd, check Metro 2033 with dual vs quad and quads 2GHz-4GHz.
http://www.legionhardware.com/articles_pages/metro_2033_performance_guide,6.html
http://www.legionhardware.com/articles_pages/metro_2033_performance_guide,9.html
Here is some really good reading with gaming CPU tests:
http://alienbabeltech.com/main/?p=13454&all=1
http://alienbabeltech.com/main/?p=14309&all=1
So I would say that most people with gaming rigs shouldn't be too worried about their CPUs.3-This just leaves a question about how good the GPU needs to be. It may be possible to approximate the GPU requirements depending on a few logical assumptions.
-If there is DX9 support:
If there is DX9 support it is not certain that DX9 cards will run it well, but DX9 mode may be there for the sake of older/lower-end DX10 cards [ie:8800/9600/9800] and then maybe the 7900 may squeeze by in lower settings. Cards below that get increasingly iffy.
-If it is DX10 and DX11 only.
-If this is the case then I would go on the logical assumption that there are certain DX11 cards that by all rights should be able to run Skyrim in DX10 at least and then flesh that list out. Starting off in safe territory, the GTS450 and HD5750 should not have a problem. Other cards in their range include the GTS250 [aka: 9800 GTX/8800GTS 512 MB] and the HD4850. These should all be safe as far as running Skyrim. Then below that there is the budget gamer cards, the strongest of which should still run Skyrim on lowered settings. These would be the 8800GT, 9600GT and HD4830.
I would be surprised if any of the mentioned GPUs [other than the 7900] were too weak to run Skyrim at all.