I noticed that overclocking graphics card doesn't matter, i use evga precission to overclock, and it gives me few fps on Heaven Benchmark , but using it on serious sam don't even give 1 signle frame so it's all CPU you need to overclock for that game, proof will come now
From what you can see that overclocking gpu i useless because ss use around 750mhz of gpu anyway (calculated by removing 135mhz because that's the value when sam is off)
So at the end i'd like to say that it's useless placing graphics card model here, better to place CPU model, or both