MSI Afterburner is in your tray, you would need to click on it and go through setting up the OSD for each listed item you want to display. But your using FRAPS (you didn't mentioned that before) so that should assist. Just uninstall MSI Afterburner, personally I seen better performance with MSI then FRAPS (less impact).
Questions:
Did you do a FULL scan, but default it only a 'QUICK' scan. Please make sure you do a full scan, just to be on the safe side, but GREAT! that it came up clean, at least nothing is holding it back!
Did you install all Windows Updates? Including options except BING? Check them and repeat till ALL are installed.
Did you download and run Slim Drivers, install all the latest updates but you don't need to reboot until you do the last update
Did you test both Single Player and Multiplayer, do you get similar results or different when playing SP vs MP (looking to see if it is your machine or your connection, there are subtle things that can affect MP but not SP)?
When your "bf4 on low , play it with 55+fps...feels like 25fps" does FRAPS show it is 55FPS at the time? Is there a particular map, sequence of events, etc. that is happening to make you "feels like 25fps". I WILL tell you that if someone does a Heli RocketPod at you, pretty much anything less then a modern gaming rig will have this happen, or say multiple Mortar strike also can do that (since your on such a low end GPU),
DVI to VGA: This is taking a highspeed highway and forcing it onto a two way side street, and is a potential problem with the low end monitor, especially if the response time is very high. In case your not aware, monitors have refresh display ratings, usually listed in Milliseconds, where it demonstrates how 'long' it takes to 'ask' the GPU for the next image to display. OLD CRTs (VGA displays) had refreshes in the 40+ms range, which was terrible with modern systems which need responses in the 'teens' to single digits. What occurs is the GPU maybe pumping out '55FPS+' but when it goes to talk to the monitor the monitor is like Hold on....... Hold on..... Hold.... hold.... hold... hooooooooolllddd.. OKAY now give me the next 'screen', but by that time 30 other screens were 'dropped' in the process (feels like 25fps).
As I don't know the specifics of what monitor you do have, but does seem lower end (VGA only and 1280*960 screen limit) I would suggest for $70 the
http://www.walmart.com/ip/Dell-DEL17LCD/20976837 for example, which is a 1280 x 1024 17" Widescreen 8 ms response time and this unit comes with a VGA and a DVI video inputs (but would verify this) according to one 'Q&A' response. This would then create a fast pathway (no matter video card) that is all digital (VGA is analog signals and one big 'lag' area) signal via DVI, with a very decent response time (my monitor and other gamer screens are 2-3ms, while your office/school monitor is around 15ms) for very little cost.
With the exception of the above questions finding another issue, the results still come down to hardware replacement, both the monitor and the GPU if you wish improved performance.