Graphics issues, games which used to run well are lagging now,

[aki64]

My system specs,
Core i5 4440 
4*4gb Adata 1600 mhz ram
DH87RL motherboard
ASUS GTX 750Ti OC edition 2GB GDDR5 

i have been able to run games like Assassin's Creed Black Flag well over 40FPS before Windows 10 installation. For a while after windows 10 installation the games worked  fine, then problems started popping up. The games lag now, i have been getting only around 6 FPS for most of my games. At first it was just for a few titles, now all the games are lagging.I tried lowering the graphics settings too. It didnt help at all( not even the difference of 1 FPS). I tried my friend's GTX 550Ti in my pc and its working fine. Before you conclude that my GPU is faulty, let me tell you that he tried my GPU in his pc and everything was working fine,no issues whatsoever, all games worked fine with no lag at all (Far cry 4 maxed out at 37fps in 1080p).
PS . all the drivers are up to date. No viruses (i have scanned the entire PC the latest and daily updated version of Kaspersky Internet security). 
Let me also add that some of the system utilities like task manager, command prompt, disk management,etc dont work often (all the more reasons to say that my OS is buggy).
I am expecting someone to reply soon. Thanks in advance.

[iWearKiltz]

3 minutes ago, aki64 said:

My system specs,
Core i5 4440 
4*4gb Adata 1600 mhz ram
DH87RL motherboard
ASUS GTX 750Ti OC edition 2GB GDDR5 

i have been able to run games like Assassin's Creed Black Flag well over 40FPS before Windows 10 installation. For a while after windows 10 installation the games worked  fine, then problems started popping up. The games lag now, i have been getting only around 6 FPS for most of my games. At first it was just for a few titles, now all the games are lagging.I tried lowering the graphics settings too. It didnt help at all( not even the difference of 1 FPS). I tried my friend's GTX 550Ti in my pc and its working fine. Before you conclude that my GPU is faulty, let me tell you that he tried my GPU in his pc and everything was working fine,no issues whatsoever, all games worked fine with no lag at all (Far cry 4 maxed out at 37fps in 1080p).
PS . all the drivers are up to date. No viruses (i have scanned the entire PC the latest and daily updated version of Kaspersky Internet security). 
Let me also add that some of the system utilities like task manager, command prompt, disk management,etc dont work often (all the more reasons to say that my OS is buggy).
I am expecting someone to reply soon. Thanks in advance.

Due to what you've said in the latter part here, reinstall windows.

 

That's my first suggestion. Much easier then finding a problem (which would most likely take longer than re-installing).

[stealth80]

Seems pretty odd, can't really even point to the PSU as the 750 uses less power. I would try some different drivers.

 

As for windows 10 I haven't had any issues.

 

Out of interest how is your ram during games? Just wanna rule out memory leak

[AlTech]

17 minutes ago, aki64 said:

My system specs,
Core i5 4440 
4*4gb Adata 1600 mhz ram
DH87RL motherboard
ASUS GTX 750Ti OC edition 2GB GDDR5 

i have been able to run games like Assassin's Creed Black Flag well over 40FPS before Windows 10 installation. For a while after windows 10 installation the games worked  fine, then problems started popping up. The games lag now, i have been getting only around 6 FPS for most of my games. At first it was just for a few titles, now all the games are lagging.I tried lowering the graphics settings too. It didnt help at all( not even the difference of 1 FPS). I tried my friend's GTX 550Ti in my pc and its working fine. Before you conclude that my GPU is faulty, let me tell you that he tried my GPU in his pc and everything was working fine,no issues whatsoever, all games worked fine with no lag at all (Far cry 4 maxed out at 37fps in 1080p).
PS . all the drivers are up to date. No viruses (i have scanned the entire PC the latest and daily updated version of Kaspersky Internet security). 
Let me also add that some of the system utilities like task manager, command prompt, disk management,etc dont work often (all the more reasons to say that my OS is buggy).
I am expecting someone to reply soon. Thanks in advance.

2 Words. Planned Obsolescence.

[Vercii]

Check your power options and make sure they're set to high performance? 

[Xenift]

Simple issue is that you have been running using the integrated processor.

Try right clicking and seeing if you have options to run with the high performance nvidia graphics card.

Also i highly doubt that you system is not valid at this point in time so the issue is 100% software related.

 

[aki64]

So guys, are you suggesting that my hardware is working fine and that the issue is only on the software side? 
but i have tried what you;ve (@xenift) suggested, and it doesnt seem to solve the issue. 
please provide an alternative solution. and yeah the power options are already in "high performance" settings.

[aki64]

The memory modules are also working fine, tried with 4 new HyperX modules (16 gigs) still the same issue. I cant really reinstall  the windows right now because it requires reformatting of my harddrives into some MBR (or GPT i am not really sure which is which,so reinstallation is not happening for quite some time i guess :/).