What would the performance difference in games and video rendering be between the i3-2100 and the i3-2120, would it be directly proportional to the clock speed (about 6%) or what? More importantly, would the four cores that the i5-2500K offers (and of course, the unlocked multiplier) be worth the extra dosh?
Need: Consistent 60fps w/ Fraps running on games like Team Fortress 2, Killing Floor, Battlefield 3 (details don't need to be on Maximum for BF3), current resolution is 1600x900 but I may upgrade to 1920x1080.
As far as video rendering goes it'd be nice to have a lower time but it's not necessary as I can leave Vegas rendering over night.
If just for the games listed go for the quad core no doubt about it. Rendering will help but a lot of cheaper software is only coded for two cores. TMPG(newer versions) Mainconcept, I believe Cinema Craft Encoder does now too. Some freeware or cheapish software doesn't use four cores or more, but I guess you get what you pay for.