is hd 6670 is a descent gaming card? ?

Don't think so. It is gradually out of date. Do you hear about new Richland APU? a A10-6800K's IGP (8670D) even outperformed HD 6670. u could read this review "AMD A10-6700 And A10-6800K Review: Richland Hits The Desktop":
http://www.tomshardware.com/reviews/a10-6700-a10-6800k-richland-review,3528.html

I've got a HD 6650M on my laptop, and it could only perform Crysis 2 in lowest setting and somehow couldn't handle Crysis 3 even if I lower every settings I could. I believed that HD 6670 DDR3 just a tiny rat bit better than mine. I won't give hope to that.