I was thinking of upgrading my 8Gb of Corsair Vengeance 1600Mhz memory to 8Gb of 2400Mhz but I was wondering how much of an impact it would have. I'm running an i7 3770 with a GTX 670 (1080p). I'm wondering if the upgrade would be worth it and how many fps it would help me achieve.
yeah fps isn't really what i would be looking for in performance improvements when it comes to faster when using a dedicated gpu. your looking at stuff like faster file access speeds, quicker load times, even faster boot. especially when coupled with a ssd.
RAM speed only matters when using an APU. The GPU portion of the APU uses system RAM as its video memory the same way a dedicated card uses its onboard RAM, to store texture data and other information. GPU performance really requires that this information be quickly accessible to achieve high frame rates. This isn't a problem for dedicated cards because they have GDDR5 on board, usually clocked at over 5000Mhz. System RAM, usually DDR3, is much slower and therefor can not provide the GPU scene information quickly enough severely limiting performance.
If you have a dedicated GPU faster RAM won't improve your FPS. However, more RAM can be useful especially for video editing and other productivity.