T420 1600MHz Ram problem?

I have brought a Kingston HyperX 1600MHz PnP kit (2x4G) 2 month ago, at first it worked out fine and was running at the 1600 speed as it supposed to be.

Recently I noticed a lot of lag and freezes on my laptop out of no where and it affected both of my Win 7 and XP system. Done virus scan on both systems and nothing turned up.

I randomly looked over my cpu-z and noticed that the ram went back down to 1333MHz by themselves and I have no idea why and when this happened. There are absolutely no settings in the BIOS about ram clocks and I did not install any overclocking programs on my system.



Q1: Is it the ram that could be causing the lag and freezes?
Q2: How do I make the RAM run at 1600MHz again?

 

I would download Memtest .iso, burn it to a CD and run a few passes, perhaps one of your sticks are bad.

 

I will do that tmr when I got time, is it called memtest86+? or is that the wrong one lol... I just googled it and that's the first thing that came up

 

keep in mind that according to intel's own specs, the i7-2620M handles a maximum of 1333MHz: Intel® Core™ i7-2620M Processor (4M Cache, up to 3.40 GHz)

the PSREFs claim the same spec of 1333MHz on the T420: http://www.lenovo.com/psref/pdf/tabook.pdf

lagging and freezing might be due to a bad memory module but it's definitely not due to a drop in 266MHz.