Antec NeoEco 620C PSU unable to handle Corsair H100i Liquid Cooler

I have a system that has Antec NeoEco 620C PSU. I am using Intel Core i5 with a high end gigabyte motherboard. There is 8GB RAM and 3TB hard drive on the same. Recently I got HIS 280X 3GB GDDR5 graphic card. I added that everything was working quiet fine. Later on I also bought Corsair H100i Liquid Cooler. That is because when I play games like Far Cry 4 on full settings on dual monitor the cpu is getting hot. I can see that in a temperature monitor app. It is crossing 70degree and I do not want to burn it. After adding the liquid cooler my pc restarts and there is a burning smell. What should I do.

Corsair H100i Liquid Cooler is an high end cooler that comes with 120mm radiator. It needs more power. I think the psu you have is not enough to handle the entire power requirement. You have to upgrade that and get a 750W or higher one. You can try Corsair CSM Series CS750M 750W. It is an amazing cooler which I am using from quiet long time. I had recently added a budget liquid cooler in the system. I am also having dual graphic cards and it works well. There is no issue at all.

Your system is quiet high end and I also think the psu is not enough to handle all the power need. 620W is quiet enough according to me but to stay on the safer side using a 750W or higher will be a better choice. Sometime due to extreme pressure also the psu is unable to deliver you stable output. In that case it is recommended to buy a reliable unit so that your hardware does not get damaged. I will also recommend you to go for Corsair 750W or higher. Corsair comes cheaper than Antec.