I recently have been getting a lot of system lag here (for example, the mouse and the display in general take about 15 seconds to react in the worst cases).
After a lot of monitoring the resources, I found that the problem mainly happens when too much Disk I/O is being done.

Three culprits have been identified:

• My browser had the highest write I/O with 35,000,000 I/O Write Bytes.
• Steam had the highest read I/O (when IDLE!!!) with 106,000,000 I/O Read Bytes.
• My antivirus (in both cases I will soon mention) was the runner up in both cases with: 30,000,000ish write and 80,000,000ish read.

The first AV I had was Avast! which I had liked on my previous system. After noticing it taking so much I/O I switched to Panda (supposing it wouldn't use TOO much during idle phase). However it only used a bit less I/O. Just a lot less memory and cpu and somewhat more network.

My browser at the moment is Maxthon 3 (which I like a lot). Before this I was running chrome which had similar data and much higher cpu when running in the background was enabled.

I'm not going to be running steam all the time and there aren't many alternatives to it.
I like my browser very much, but I AM willing to switch if there's an obvious problem (I'm in programming, however I'm not a very good sysadmin, especially not when it comes to windows).
Finally, my system almost stops lagging when I turn off the antivirus (and preferably steam) (some remains but once in every 5-6 hours for a few seconds so it isn't a big problem).

My question (has a few parts):

• Is it possible to configure steam to lower it's I/O usage? (and maybe network while we're at it?)
• Which antivirus (very preferably free) uses lowest I/O while idle (I leave PC alone during active scans so that isn't a problem).
• Is there an obvious problem with my current browser and, if so, is there a way to fix it or should I switch and, if so, to what? (P.S. I've been on FFox for some time too).

Info on system:
Windows 7 (32 bit T_T, I am getting a new one in a few months but I want to keep using system during that time though).
Hard Drive (main) is a Raid0. (Also have an external 1TB one which contains steam (and steam alone). As such it doesn't get used by much anything other than steam and isn't a very large problem. However steam still uses some I/O of registry)
CPU: Intel(R) Core(TM)2 CPU [email protected]
RAM: 6GB (3.25GB usable) (this and CPU have little effect as shown in next section)

Additional info:
Memory usage during problematic times: 44%
CPU usage during problematic times: 35%
Page File: main drive: system managed. 1TB drive: none.
The current system I'm using is about 6 years old and is mainly a place holder while I await the new one in a few months.

Final words: this is my 1st post on Super User (this question wouldn't feel right on Stack Overflow where I usually stay). If it doesn't have it's place here please tell me. If anything is wrong with it, same.

Edit
Technically I'm looking for a live thread detection program with minimal IO usage. I already have good active scan capability: Kaspersky (the free scanner uses the paid database) and MalwareBytes.

Edit 2

Noticed another one, it seems that windows media player has been using stuff even when off! Turning it off and restarting now. If the problem is fixed I'll tell you guys. The reason I didn't notice it before was because I didn't have resource manager in front of me at the MOMENT of the problem. Now I did and it was at the very top of the list!