The Power D-Sub have peplaced the two rows in a Standard Density connector with a power contact that take up about the same size as the two rows of signal contacts. The Power D-Sub is exactly the same size as the STandard Density connector but instead of example 9 possitions of signal pins it has 2 power contacts , or instead of 37 possitions of signals it has 8 power.
The Power contacts are available with current rating ranging between 10A - 40A with only the size of the terminal being different.
The Power D-Sub with Mixed Layout is a very popular connector and that it is for a reason, as the name apply, the connector mixes both power contacts and signal contacts in the same connector. For example the same size as a 15 position Standard Density D-Sub you can have what we call a 7W2, which means there is 7 contacts where 2 of them are power contacts, which means there are 5 signal contacts, so 5 signals and 2 power. See the Layout in the Tech Specs on the bottom, there are a lot of combinations of the Mixed Layout alternative.