FPS lag spikes

Hello, I'm posting this in order to find some help, I fully appreciate any kind of answer that relates to my problem, hopefully people with the same will find great help in this post.

Here I go, I own a laptop : Travelmate 5742g.
Intel Core i5-480M 2.66Ghz (can be boosted up to 2.93Ghz with turbo)
Nvidia Gefore GT 540M 1024MB VRAM
4GB DDR3 memory
500 GB HDD (not even half occupied)

I used to play games like Mafia 2 / Assassin's creed 3 / Battlefield 3 and such perfectly with medium / high settings without problems, but now regardless of the game's requirements, It seems that after a period of time the games start lagging, dropping my fps from nearly 45 to 15 / 20, I suspected that my fan was dusty so I cleaned it up but the problem still persists, I'm asking you to help me find out the answer for those lag spikes, Is it a malware infecting my pc ? if so what are the tests I should run ?

Thank you so much for you replies, god bless you all.

I know this sounds stupid but I made this mistake just the other day.
I turned on power-saving mode and forgot to turn it back.
Go to control panel - Hardware and Sound - Power Options
Ensure your not running on a power saver mode, and if in doubt, click on the "Balanced" option.
Also, it might not be a good idea to have it on "High Performance" since that can cause quite a bit of heat.

Personally, I prevent any programs from starting up with the pc/laptop.

Open task manager and just check to see whats going on in there.

Download speedfan and check the temperatures of your hardware. (I once made a sloppy job with thermal paste that caused some problems.)

Thank you for the reply, sorry to tell you that that's not the problem, I checked it before and everything is set properly :/ thank you again.

Maybe some applications is running in the background using more cpu, have you tried checking task manager when you are having FPS issues? Did you install some updates/drivers or codecs? Did the fps lag occured during something like loading new area that requires reading data from the hard drive? Try runing checkdisk and defrag your drive.

Try the following:

• Update to latest Nvidia graphic drivers. Before updating, make sure to do a CLEAN and thorough uninstall of your current GPU drivers.
• Check GPU temps and CPU temps. If one is overheating and throttling - all sorts of problems could arise. If temps seem higher then normal, go ahead and open up your laptop and do some cleaning. Usually, all you will need is a can of compressed air for such a task.
• Do a couple Virus/Malware scans. I doubt it, but it is possible you could be infected.
• Pull up task manager and check to see your CPU load. Is there a particular process eating up your system resources?

Let us know how things turn out. Hopefully, some of our suggestions will help you narrow down the problem.

Add another 4GB of DDR3 RAM that's what I did in my new Gateway with i3 inside. Ran much better. I have mine tweaked but the RAM for the system was cheap only $20 bucks in July 2012. I am mostly AMD CPU guy but still have some Intel's around. Intel HD inside the laptop really better than prior Intel HD. Anyway make sure you remove all Norton Bloatware with the free Norton Removal Tool you get that from Symantec for free.There is one more tool to use to get rid of Norton Backup. The way new systems come so loaded with bloatware. Just don't need that running in the background. Set the CPU from balance to High Power too. Otherwise that 2.66GHz will be like 1.33GHz.

High performance is the best option when gaming on a laptop, but only when your plugged in since it kills battery. I notice my fan works more and temps are higher when under high performance but if he cleaned the fan out that should not really be a huge issue. As Blkfx1 said above, update nVidia drivers (clean install through custom install) since some new issues could arise with new patches (I notice this with BF3).

The HDD has nothing to do with FPS usually.

In general, go to task manager and check for me, what is the CPU usage and memory usage. If the CPU usage is high and nothing is really running in the background, it means there could be some sort of malware. As for RAM, I notice that games adapt to my 4GB of DDR3, only eating up about 80% of it in total (with system). So this probably isn't the issue. It is most likely a driver issue so updating will help.

Turning off turbo boost in the BIOS will kill battery if you use it on the go but will increase performance in game since it wont fluctuate between clock speeds.

I actually it does, have you played Skyrim? When you walk to new unexplored area the game loads new data from the disk on the fly. If you have major disk activity like copying huge files you will see major fps drop during the transition. So as bad sectors.

FPS isn't dependent on your HDD. Only thing your HDD influences within a game is load times / speeds.

Yeah. Maybe games like Skyrim (RPGs), in which require fast HDDs may be effected, but mostly with load times.