Computer slow after upgrade

[Aron Vajda]

I bought a new mobo, cpu and psu, installed a fresh windows and the computer has its moments when its even slower than my old one. When I start a game it's going on pretty low settings. Checked the hdd and it's healthy. CPU temp never went over 50. The thing i noticed is I get random cpu peeks. Checked in taks manager what caused it and sytem idle process is jumping between 70-98. Is this normal? Also there is a update for bios, and I'm not sure should i update it.

Configuration is:
Gigabyte h97m-d3h
Intel i5 4690
Asus HD7750
2xWD 500Gb
2x2 Gb Ram @ 1333Mhz
Seasonic M12II 750w

What is the reason for slow computer? What should I look at?

 

[vrumor]

You have low memory and a low end video card. Id start there.

 

[Darthutos]

well what specs do you have on your old one?
differences in OS? Different hdd? Different Memory speed?
I'd add a SSD instead of the memory and gpu first.

 

[Aron Vajda]

I had intel E7500, gigabyte p43t, and 400w Chieftec. Same OS, HDD and memory. I am planing on buying an SSD, but why is the computer slower/ laggy? Also is the sytem idle process OK?

 

[Aron Vajda]

And should I update Bios?

 

[Darthutos]

Have you checked for viruses?