Standard DRAM Memory

[cooler813]

I bought the ram CT25664(http://www.crucial.com/store/partspecs.aspx?IMODULE=CT25664BC1067) for my new thinkpad T400 and it will not boot up my computer.

The sales rep I dealt with said this is a compatibility issue because CT874366 is the right fit (http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=BC695BDFA5CA7304)

He said "Most likely the issue is that you are not using compatable RAM. Just because they match up spec wise does not mean that substituting it out will work for you. The main reason why companies produce a series for certain notebooks is because it only detects certain densities of RAM chips but there generic RAM they use whatever they can build it with."

The specification looks exactly same to me, and i do see people confirm it works with thinkpad. Could you please advise the differences between these two models?

Thanks

[Crucial_maulmod]

Hi cooler813,

The two parts are the same.  When you order online by system information, you are shown what we refer to as an “external” part number, in your case number CT874366. It is a system specific number and is mapped exclusively to the Lenovo ThinkPad T400 Series. The longer part number, CT25664BC1067, is the one that would you see printed on your module, and that is the actual module part number, or the "base" part number.

Sometimes we are required to filter out a certain build of a part for a specific system. The external part number can accomplish this, since we can build filters into them when necessary so we always recommending order by system to guarantee compatibility.  As far as I can see, there are no problems with this part and your system so it should be compatible.  We can try a bit of troubleshooting to resolve this issue.

Firstly, please try the module on it's own in each of the slots, this will help determine if perhaps there is a fault with the modules or one of the slots. As you are installing them, please follow the instructions which can be found at the link below:

http://www.crucial.com/uk/install/sodimm.aspx

Once you align the notches, install at a 45 degree angle and put a bit of pressure on the module so that you hear a click before you slide the module flat into the slot. The gold pins should practically disappear from view once it is fully seated.
If you are using this module with an original part, please ensure that you install the largest one in the first slot.

Please also make sure that you have the latest version of the BIOS installed from the manufacturer's website.

I hope this helps but please get back to us if you require further support.