How to check whether my system RAM is DDR2 or DDR3 [duplicate]

Try CPUID:

Direct Download: http://download.cpuid.com/cpu-z/cpu-z_1.74-en.exe

Downloads: http://www.cpuid.com/softwares/cpu-z.html

After you installed it, go to the Memory tab, your answer is there.

DDR2 ram has a sticker on the dimms labelled PC2-xxxx DDR3 ram has a sticker on the dimms labelled PC3-xxxx(x)

Even if there is just a barcode on it, you can google the number and it will show you what type of memory it is.

You can also visit a site like kingston.com or crucial.com, enter the details of your computer make and model, and it will give you a list of compatible memory.

Just in case you can't or don't want open your computer, may be the free tool Speccy (System Information) will give you the information. You can download it on Piriform web page , choosing the free version.

Also you can find a portable version on Speccy - Download Builds just in case you don't want to install in your PC.