Which Graphic Card is better

I live in entirely not advanced 😀 country and when I want to make a hashing rig and there is not a lot of gpu choices 

So I have two options and I can't find anything to help me stat one of the graphic card (Option 2) so I can't make my mind and I don't know how to decide which is better through it's specification

Option 1:
2x Gainward GeForce GTX 750 Ti 1 Gb GDDR5

Processor Core = 640 cores
Base Clock = 1020MHz
Boost Clock = 1085MHz
Memory Clock = 2700MHz
Memory Size = 1024MB
Memory Bandwidth = 86.4(GB/Sec.)
Memory Type = 128bGDDR5

Total processor cores = 1280 core (640*2)
Total memory size = 2 Gb GDDR5 (1*2)
 
Remember I will buy two of those !

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Option 2:
1x Gainward GeForce GTX 670 Phantom 2 Gb GDDR5

Processor Core = 1344 cores
Base Clock = 1006MHz
Boost Clock = 1084MHz
Memory Clock = 3054MHz
Memory Size = 2048MB
Memory Bandwidth = 195.5(GB/Sec.)
** Memory Type = 256bGDDR5

this option is bit more cheaper than option 1 but I need to know if it is any faster than option 1 and Why

and I would like you to know that I don't have except these choices