I find it really inexplicable. I'm not saying i don't believe you guys, i just find it very strange that i have a two year old middle ground PC and i have seen nothing but improvements in performance with every single patch.
Seeing people with much beefier rigs than mine get a "lottery effect" on each patch is very confusing to me, especially for those that follow the proper patching guidelines (clearing cache, defragmenting the game folder through steam, etc).
Just for the record, i'm running on an i7 920 @ 2.7 GHz with no overclocking, windows 7 x64 pro, an Ati 4890 1GB and a measly 3GB of RAM. I run mostly medium settings (a couple are set to low so that i can set a couple more to high) at a 1680x1050 resolution and the only time i get lower than 25 FPS is when skimming rooftops over London (flying at 300ft or lower).
On one of the stock QMB ground attack missions (the one where you spawn in 110s a bit outside Manston) i have measured up to 55FPS and that was a couple of patches ago.
It really seems weird to me