Can new ram be reason for pc freezing

I have a Windows 7 based pc. And I had seen that my PC freeze for no reason. It occur on boot or sometime when I play game or when I am working. It is very common that the pc freeze when I turn it on for sometime. I checked the RAM and I had tested it with Memtest. But it is not able to find any error. So that is fine. Then I ran OCCT and tried to test my pc for performance. But I did not find anything wrong in that. So can anyone tell what all things can be the cause of freezing. I am not able to play games properly.

Is your is overclocked?. If yes then this can be the reason. Because I had seen in few years some products are just average. They are not made from good quality. For example I have a a good high power psu in my home pc. And this just burnt after 8 months of use. Luckily I was having a warranty where I got it replaced. After a few months when the warranty was over I switched to Earthwatt Antec 500. That gives me the same kind of work but it is far more reliable. You might be having some kind of power problem.

For such purpose when it comes to gaming SSD's are the best one. They are reliable and good. They can give you good performance and it wont lag or cause bottleneck. It is always good to buy things from a trusted hardware partner. People go for cheap on that does not give them performance and then they cry for output. So here you have to start checking from the start once. Make a list of hardware you want to buy and then choose the best and reliable brand if you need a optimum output.