Startup - no one would expect you to work there more than a year unless it was well funded and therefore paying fabulous salaries.
Second place your were there for 3 years.
Third place - 7 months. It's possible that a particular place does not suite you. Exceptions are not a rule and HR understands that.
So changing to a third company for a 50% hike is pretty correct and accepted. But you must go only if you are sure it's a longer term move. Another 3-6 month stint will be bad on your cv.
However, also realise that your current company is unlikely to take you back a third time if you didn't like the new one you are going to ......
Lastly, in today's scenario, refusing a 50% hike is kinda stupid
worked with startup for a year .Then moved to MNC A and worked around 2.5 years. Then went to MNCB and after 8 month due to job profile change i moved back to MNC A but with no hike. so it is just 6 month with my current job and i am not too much happy with it. Now i got offer from qualcomm with 50% hike, although i declined but they are still persuading me.. i am also not sure i will be happy there .... i am in complete confusion and once i read somewhere that You shouldnot change your job if u have even 1% doubt??
Your query is quite irrelevant!
Even after knowing the names and the reputation of the companies, when you are not sure whether you will be happy there or not, how you have expected from the members of the forum to judge merely ABCD whether you would be happy or not there without knowing the names and fame of the companies and and your job profile, how anyone can advice you whether your decision is foolish or right to continue with same job?
Can you please clarify on this point. So, if you are unable to share with the basic necessary information about your job and the companies, better stick to your own decision, whether foolish or right, as based on your own wisdom.