Difference between 64K and 128K SIM Cards

A Subscriber Identity Module (SIM) card is inserted into a mobile phone. The SIM card is used to uniquely identify a user of a network. A SIM Card is used to store messages and contact information. It also stores information about the tower it is connected to and the authentication key of the subscriber. There are various variants of the SIM cards. The ‘K’ represents the kilobyte of memory available in the particular SIM card for storage.

The earlier variants of the SIM cards contain 32 kilobytes of memory while the more recent versions have 64, 128 and 256K memory. This memory information is usually mentioned on the SIM card. The higher the memory space, the more recent it is and the more features it has. The newer versions are used for 3G, 4G, and LTE internet connectivity. The latest versions, 128K and beyond have tracking systems in case the mobile phones go missing.

Difference between 64K and 128K SIM Cards :

S.No.	64K	128K
1.	It was very popular before 2003.	It has become more popular than 64K SIM cards after 2003.
2.	It can be used to store contact information of about 500 people.	It can be used to store contact information of about 600 or more people (approximate value, as it depends upon the provider).
3.	It is used for 3G and 4G data services.	It is used for 4G and later data services.
4.	It does not have computer synchronization and recovery in case of theft or loss of mobile devices.	It has the feature of computer synchronization and recovery in case of theft or loss of mobile devices.
5.	The network operators can run less mobile network operations on it because it has lesser storage.	The network operators can run more mobile network operations on it because it has more storage.
6.	It has 64 Kilobytes of storage space.	It has 128 Kilobytes of storage space.
7.	It may or may not have SMS lock, auto roaming and direct access to social network accounts, depending on the povider.	It has SMS lock, auto roaming and direct access to social network accounts.