Hi there,
I noticed some Nvidia cards come in both 2 fan and 3 fan models. Apart from the difference in length, are there any design changes that would impact on hash rate? There seems to be $200-$300 price difference between the two. If no technical difference between the two then buying twin fan model would be the cheapest.
If you buy a video card for mining for installation in an open case or a PC, and do not want problems, then it is better to buy a video card with good cooling. Even a $ 200 overpayment for good cooling will pay off in a few years, but not every expensive graphics card is good.
I recommend that you read the reviews of miners before buying. If you use closed cases, then you can get cheaper video cards.
The processor is not the same, and the hashrate is strongly influenced by the memory manufacturer and overclocking capabilities.