Thanks St1ckM4n - not too sure where to start !
To answer the OP's question...there's a lot of variables in play. Presently, AMD's processors (talking about the FX series for the most part) really require very optimized code to shine. Benchmarks, for the most part are oversimplifications of a complex data set made graphically easy to understand (
Tom's periodic comparisons for example, or
Hardware France's almost-every-cpu-in-existence historian's-porn ). Almost any real world usage is going to have to take into account multiple processes run concurrently (browser + AV + monitoring + various programs and startup utilities- Steam, mouse/kb gaming software, Adobe Flash etc etc), and very few sites run those kind of benchmarks
(bit-tech's approach here).
Clifford's assertion of Intel's superior instructions per clock (IPC) is correct. AMD chose the approach of a long pipeline running at a faster clock to counter Intel's lead in IPC. Unfortunately each 2-core module in Bulldozer/Piledriver has shared resources which cannot be fully utilized by both cores at the same time. While integer performance is good, AMD suffer from shared floating point resources - along with high latency and a relatively inefficient cache....so, YMMV when it comes to what kind of performance you can expect (and in comparison to Intel) based upon what mix of applications are running. The more single thread programs with their inherent serial nature, the better Intel looks. If on the other hand, you run an esoteric mix of heavily multi-threaded/parallelized apps running concurrently, the AMD's comparison looks more favourable with Intel. Unfortunately for AMD, most code in daily use for consumers is weighted more towards the single thread.
A more in-depth analysis of the relative architectures can be found at Real World Tech. Dave Kanter's
Bulldozer analysis,as well as
Haswell.
I am pretty interested in AMD for my next build after the rumor today that next gen AMD CPUs will use GDDR5 onboard memory + DDR4
Technically the "CPUs" you've heard about are APUs (Kaveri), and that launch is near the years end (assuming the AMD timetable remains valid -
. Kaveri is the successor to the "Richland" series of APUs that are supposedly being launched this/next month.