Valve's head man Gabe Newell mentioned earlier this year that sales of their games tend to spike when they have price cuts on Steam. Now a new study seems to confirm that player activity for their zombie shooter Left 4 Dead has gone up for the PC version compared to the Xbox 360 port of the game.

Gamasutra reports that a new study from DFC Intelligence and the social networking site GamerDNA shows that player activity for both versions of the game were more or less the same until Valve held a 50 percent sale of the PC version on Steam in February. PC player activity went up and then leveled off but still was somewhat higher than the Xbox 360 version.

In late April the free Survival Pack was released for both platforms and while both the PC and Xbox 360 experienced spikes in player activities, the PC version went even higher thanks to a "Free to play" weekend that the Xbox 360 version could not duplicate. Since then the PC version has continued to be much higher in terms of player activity than the Xbox 360 port.