Computer Underperforming?

[Kwanzilla]

Hello, I have a fairly decent computer yet I feel that my computer is running slower than usual.

I have:
gtx 570
i7 2600k
4gb of 1600 ddr3 (the other 4gb is being replaced)
ASUS P8P67 LE (REV 3.0)
1000W PSU
SATA III 1TB HDD

I feel like this computer should handle everything thrown at it with no problem, but still experience some lag while doing typical tasks. I have a feeling something is malfunctioning. Any help would be great.

P.S. - I also have issues with programs crashing and my screen randomly going black for a few seconds. This is probably related.

 

[geofelt]

Some ideas:

1) Is it possible that you have a virus or malware?

2) Run memtest86+(get the latest version for sandy bridge). You should get NO errors for a couple of full passes. Is the ram supported on your motherboard?
Check the motherboard QVL list, or the ram vendor's configurator.

3) Run Prime95 with rounding error checking. Run long enough to get the temperatures up to the max.
Are there any errors? Is the temp >70c?
Does it downclock?(check with cpu-z)

4) Update the windows experience index. What do you see for the individual components?

5) Is your Nvidia driver current?

6) Are there any relevant Bios updates not applied? Don't apply anything unless it will fix a problem. A failed bios can brick your motherboard.

7) What model of 1000w psu do you have? It seems like overkill. A flaky psu can cause your type of symptoms.

 

[ohiou_grad_06]

I would test your hard drive. I worked on one like this recently, tested everything I could, turned out to be a random problem with the hard drive. Replaced it, PC now runs like a top. Do go ahead and run Intel Burn test on the processor, memtest on ram. Also run furmark for 30 mins to stress the video card. If those test good, I'd say you are either looking at motherboard or hard drive.