Upgrading for a crucial reason!

Hi everyone! I'd love to ask you some things since it's been bugging for a long time now. I want to upgrade some parts but there is a reason for that. Just to say my pc is around 2 and a half years old now. So 1 year ago it started something like freezing while gaming. It would just stop for a second and it would happen like 5-6 times a day. Sometimes it didn't freeze but rather I had fps drops quite often. I didn't mind it at that time since it's wasn't so bad! It was playable , at least. But now I'm trying to play this game called osu!. If you haven't heard of it it's a rhythm game where you click circles to the beat of the song. Thing is , my cursor would either skip frames,the game would freeze,the cursor will somehow do a really slow movement towards a circle even though I moved my mouse really fast to the location I intended it to go. If anything like that happens I would miss a combo and it really hurts my heart. I want to upgrade some of my parts but I don't know what could be causing the problem. Here are my specs.
CPU: AMD Radeon FX 6300
GPU: AMD Sapphire Radeon r9 270x
HDD: WD Blue 1 TB SATA 3
RAM: Hyperx Fury 8GB,DDR3,1600MHz
Monitor: 60hz ,1ms response time

I had in mind to upgrade my hdd since something happened to it a while ago and couldn're read correctly so I had to give it to be reinstalled new windows. I can't remember if the problem occured after the crash or not though :(. Or would an SSD be better? If that is the problem of couse. Maybe the RAM? I need to know guys. The other thing is that my pc gets really hot. It's not in a good case because a bought a cheap one when I was building it. It has water cooling but it didn't change the temperatures much after it was installed. The highest temperatures were on my GPU and CPU. Can't remember the exact ones but I can download a software that can tell you if you think it's important. I tried asking in different forums but didn't get any good response. I was told to update all of my drivers which I did but nothing changed.

Thanks in advance!
-Frosty

@frosty11: What are the temps? if they are too high, the CPU will downclock itself to prevent damage, same with the GPU.

It could also be a bad stick of RAM, download and run memtest.

I'll make sure to give you the info when I get back from school. About the CPU downclocking, I think it might be it but only in some newer games since it gets hot when I play something like Black desert or GTA V. The rhythm game I mentioned is the only one that doesn't affect the pc's temperature and yet the cursor still keeps stuttering while the game is still going smoothly. It might be a different case with it.

@GTR12: When I don't game my CPU is at 40C - 44C and my GPU is at 31C - 32C. When gaming it looks like this : CPU 58C - 60C and GPU 50C. So about the memory test, I only did the usb thing where it puts files in it and what am I supposed to do next? I know I have to restart the PC but after that what? Also what do you think about the temperatures?

You need to restart the PC, but without booting into windows, you boot into the USB instead and follow the prompts.

What program(s) did you use to monitor the temps? They are both ok, can you try another temp monitoring program, just so you are getting accurate results?

The first temperatures I gave you are from Speed fan. Now I used FW monitor and the only difference was in the GPU where it would show the max temperature is at 67 C. And about the USB thing, it doesn't seem to work for me. Nothing happens when I restart my PC while the flash drive is pluggedi in.

Temps are fine then.

Follow one of the steps below to boot from USB, its not as simple as plugging in the USB and having it work.

https://www.tenforums.com/tutorials/2294-boot-advanced-startup-options-windows-10-a.html