Games lagging with 100% cpu utilization

[deepagg1]

My PC config:-
CPU - Amd Athlon II X2 270
MOBO - Gigabyte ga78lmt-s2
RAM - 1333Mhz DDR3 4GBx2 (just installed one)
Graphics - MSI nvidia GTX 750 Ti (just replaced zotac GT520)
PSU - Antec 650W (just replaced Mora 500w)
Cabinet - Mora normal with no fans

After replacing the GPU, games are started lagging and stuttering on my PC. I checked the resources at that time, Ram was sufficient but CPU is 100% utilized constantly. When I was having my old GPU the games didnt lag but graphics were poor. Now graphics are very good but system started lagging. Somebody told me to replace the PSU so I replaced it with Antec 650W and installed one 4gb mem stick. but now after spending a lot on this I'm facing the same issue as my CPU is utilizing 100%. After prolonged gaming when I touch my cabinet it's very hot.

Now I'm thinking of overclocking the cpu on this machine but I dont know how. Is this the right thought? Please suggest as I dont want to spend more on cpu and mobo at this time as I've already spent a lot on other parts.

And Please suggest the steps to do this.

 

[Vic 40]

Still have the old psu? Tested with it?

 

[deepagg1]

not tested again

 

[Vic 40]

It wasn't just a question,but a suggestion as well. 😉

 

[deepagg1]

what are the possible solutions behind this suggestion? what can it be?

 

[Vic 40]

If with the old psu the temps go down again you know it has something to do with the new psu,might want to consider an rma for the new one then.It shouldn't make temps go up,it's something new for me but it shouldn't happen.

 

[deepagg1]

Not tried still. If I replace my CPU with FX6300 by investing a lot of money, will it solve this problem of games lagging and stuttering and high temp problems?

Or should I try installing any good CPU cooler for around Rs.2000? Will this solve my issues?