Well the only thing we can do is to give the specs on the computer tested on. Like OS, Ram and processor, like you said. Because it is a little easier for people to get a feeling of how their system will operate.
So lets say i tested an older game who gave me 40 fps on average. I have Windows 7, 1.8 Ghz dual core processor and 2 GB of DDR2 RAM. And we have a guy that have Windows 7 also but have an 1.6Ghz dual core and 1 GB of DDR2 RAM. Then he would know that at the best his system would meet me, but most likely it would be around 30-35 instead. So i think it is a good idea, cuz if you say that Counter-Strike Source runs at 100 fps on the x3100, people would be crazy and saying there results don't add up to that. And later we get to know that the computer had monster RAM and a monster CPU. So information is the key. -- INTEL 9xx SOLDIERS SANS FRONTIERS
