T420 Identification

[PhoenixR]

I've been offered a T420 lately so I decided to clarify its configuration first but couldn't find a relevant info based on its type number.
I am on T400 right now & from what I have gathered the major key differences between the models are: i3-i7 35W vs Core2D 25W CPUs, integrated Intel OR discreet Nvidia NVS(never both) vs hybrid Intel + AMD (in some types, including mine) GPUs, LED vs CCFL (majority, including mine) screens. Is there a booklet or any other source with this kind of info helping to identify the exact configuration of a given T420(including 420i, 420s, still having just a very vague idea what is the difference between 420/420i/420s) based on its typexxxx-xxx number?

[RealBlackStuff]

Search the web for: lenovo t420 psref
Change t420 for any model you want.
PSREF has all the info you want.

[axur-delmeria]

Use the MTM link at the top of this very website, just below the site banner. It's between HMM-Manuals and Feed.

Enter the MTM without hyphen (e.g. 7676A27). Good luck.