[SOLVED] Sudden FPS drop??!! Help!

[neil.jadav26]

Hey guys,
Recently I upgraded my GPU from a GTX 750ti to a GTX 1070Ti because I wanted more FPS and overall performance. For the first week after I installed my new GPU, games were running absolutely amazingly. I play Fortnite and GTA V. These games were running perfectly. On Fortnite I was playing at epic settings and managing 100-120 FPS. On GTAV with very high settings, I was managing approx 100 FPS. But, after the first week, one day I turn on my computer and load into GTA V and realized that my FPS was dropping significantly. I was so confused so I tested Fortnite and also realized the same problem. I am very worried and don't know any fixes for this issue.
My specs are;
CPU: i7 6700 (Non K)
GPU: Asus GTX 1070Ti ROG Strix 8GB
RAM: 4GB DDR3
HDD: 2 TB
SSD: 128GB
PSU: 650W
Appreciate any help that will be suggested.
Thanks

 

[SubaruWRX244]

Why do you only have 4GB of ram? Theres your issue!

 

[neil.jadav26]

Why do you only have 4GB of ram? There's your issue!

I figured that would somewhat bottleneck my system beforehand that's why I ordered another 8GB of RAM off Newegg before I purchased my GPU. I'm just waiting for it to be delivered. But I was also wondering that if my RAM is the issue, then why did it only kick in after about a week?