The gpu is gtx 770 4gb- the real problem persists with Tomb Raider, Stalker Call of Propyat, and Alan Wake Gog version. I have checked and monitored the card for overheating but temps remain normal for that load. Could there be an issue in the card being faulty or do I need to reduce the clock speed?

What do you consider "normal for that load"? Anyway, if the temperature goes beyond 100 °C it is most likely overheating issues. In my experience you shouldn't ever require to clock a graphics card down from its default settings but if you have actually overclocked it you should revert the changes, at least to check whether the issue persists. And well, most of the time if there's a hardware problem it is connected to insufficient cooling caused by dirt or a faulty fan or something (in my experience).

Also, do you actually mean full freezes or just a kind of stuttering?

Have you checked in the specific game forums for an answer? Let me get some links for you...

Here's the community game forum for Tomb Raider
http://www.gog.com/forum/tomb_raider_series#1386960980

The game forums might not have been immediately apparent but they've been super helpful to me in the past...

I'd first check whether this might be related to the drivers or not.

Which OS and set of drivers are you using ? Is your system overclocked ?

Right, especially with the faulty drivers that Nvidia has already released a while ago at least for a few models. I haven't heard of issues related to the 770 yet but who knows, maybe it's their next victim of terrible QA.