hardik29

Most likely your laptop is overheating. Did you use canned air to clean out the fan and heatsinks? If your feeling a bit bold, you can take apart the laptop and reapply higher quality thermal paste. 

That is definitely a good suggestion, but first - I think OP needs a laptop cooler - I had the exact same issue with my laptop - then after few months I've decided to get one of these bad boys,  and boom,  works,  can play for hours and it doesn't throttle...
 
But: do not ever plug the laptop cooler into the laptop,  use an external power source.  You have been warned.
 
Reasons: should be obvious,  first it can damage your laptop by drawing too much power or cheap USB cables / connections and second since it draws power it can make the laptop throttle again,  this time for power and not heat..  But the risk of damage is obviously a lot more serious so just use external power and there's no issue simply. 
 
 
 
 
 

You should really try what i mentioned to you first before you go down that rabbit hole.
 

I'd go for NAS4FREE as its a forked version designed for lower ram amounts. Worked well for me

You should be able to yes. Your experience may not be the greatest but it should still work.

you should start by turning off caps lock..
 
but yes, you can, it'll most likely not perform optimally but it wont absolutely crawl either.
 
that said, dont touch stuff like ZFS, or its advanced features.