Here is one explanation why AMD performs better when you run more advanced games and also run them on high res.
It is the same reason as why AMD is strong on servers even if Intel Xeon is higher clocked.
It’s about communication with other hardware (memory and GPU).

When Intel communicates with other hardware it sends data using the FSB. All traffic goes through the FSB. The Latency using the FSB is about 250 clocks. The performance penalty is rather large. If one game is reading memory and/or sends I/O to the GPU using only one thread. Then I don’t think you will see any big differences between AMD and Intel. If the video card is slow you defiantly isn't going see any differences.
Now if the game is using more than one thread the situation changes. If one thread is sending or reading data on Intel, and another thread is sending data to the video card. One of the threads needs to wait. That means that latency goes up. In worst case scenarios it would be double (about 500 clocks).
On AMD this is handled differently. AMD has hypertransport that handles I/O to the video card. If one thread is sending data to the video card it doesn’t compete with memory. On AMD latency is a bit lower too.
Running games on low res or games that isn’t that advanced then this isn’t a problem on Intel. But if you are running a game on high res, have a fast video card (or two). Then this video card is able to handle VERY MUCH I/O. Also if the game is using more memory then more data needs to travel through the FSB on Intel. This situation will lead to more conflicts in the FSB and latency is increased.
Intel is very fast when it isn’t disturbed and is able to use data in the cache. More threads, more memory, more communication with video card and maybe more synchronization between threads. Then performance will shift to favor AMD system design.