The Panasonic Toughbook CF-31 comes in 5 different sub-models. The CF-31 models range from Mark 1 to Mark 5 (or MK1 to MK5). When Panasonic first releases a new Toughbook model it is a Mark 1 or MK1. The next generation would be MK2 and so on... The difference is mostly in the internal hardware such as faster CPU or other upgrades.
The biggest improvements for the Toughbook CF-31 line are going from an MK1 to MK2 since the MK2 models are able to handle up to 16GB of ram vs. a maximum of 8GB for the MK1 CF-31 units, other upgrades are a faster CPU speed, etc... We normally recommend the CF-31 MK2 model or newer just for the ram upgrade alone can make a noticeable speed difference with 64 bit versions of Windows 7 or 10 running.
How do you know which Mark or MK model you have? You can check the bottom label that looks like this below. In this example this unit is an MK1 model. The character that comes after CF-31_ will determine which model you have according to the chart below.
Sometimes if the units have a lot of wear this label could either be missing or unreadable. So you can can also check your BIOS by pressing the F2 key when you see the BLUE PANASONIC screen after turning on your Toughbook. In the example below this is an MK3.
The character that comes after CF-31_ will determine which model you have
CF-31 MARK FIRST 3 DIGITS
MK1 CF-31A, CF-31B, CF-31C, CF-31D, CF-31E, CF-31G
MK2 CF-31J, CF-31K, CF-31M, CF-31N, CF-31P, CF-31Q, CF-31R
MK3 CF-31S, CF-31U, CF-31V
MK4 CF-31W, CF-31X, CF-31Y
MK5 CF-311, CF-312, CF-313, CF-313
This is also critical if you want to order one of our Hard drive caddy packages for the Panasonic Toughbook CF-31. Click here.
I hope that helps clarify any confusion. If you have any questions please contact us.