I want to chime in with the set up I have being that it is far below par but still runs smooth with graphics on par with oblivion on ultra settings.
Compaq Presario CQ56-115DX, 2.1Ghz V-140 single core CPU, 8GB RaM, integrated radeon mobility 4250, 10-20 Gb page filing, Catalyst AI set to quality high and the CPU to 100% continuous, not over, the catalyst AI over rules Skyrims settings and plays the video through a different set of protocol and allows me to boost performance like over clocking my display and pushing my CPU. when I loaded up Skyrim it auto set me to medium quality.... Not smooth though so I set it to LOW and put textures at medium and set the Catalyst AI to run over Skyrims settings for the most part. Smooth game play and fair /good graphics, although sight distance is hampered and set to close proximity, but I do not freeze, or watch a slide show,30fps running and jumping, casting spells is all quick and responsive with no trouble. No bonus video quality over Oblivion though...

All in all even single cores with sub par settings in certain areas can still make the grade. I stand by my word to everyone that if you can run Direct X9 and can max out Oblivion, then you Will be able to play Skyrim with out having to loose out on too much hard core graphics. I admit I am not running in HD and have to scale it down to 800x600 but everything looks great, just like oblivion. Even better, and considering that it looks as good on medium to low settings as oblivion on max tells me when I build a new computer that this game is going to get me wet with blood when I split skulls.
(Catalyst AI made all the difference, other then adding the RAM upgrade the computer is a stock $300 low end laptop from best buy, not to shabby for a entire computer that cost as much as the i7 Core I bought for my new build Im working on........)
Look for my review in the discussion thread under Hard Core Gamer's Crotical Review