Counting Processors

Two types of licenses are distinguished: host-locked (most typical license) and floating.

Host-locked licenses

The minimum amount of cores that can be licensed is 8. Additional options are 16, 32, 64, 128, 256 and unlimited cores (see also pricing table). The total number of cores can be on one or multiple machines. We count the total number of physical cores on all licensed machines. For processors with E and P cores, only the P (performance) cores are counted.

NOTE: It is not possible to get a host-locked license for a subset of cores on a given machine.
We cannot provide an 8-core host-locked license for a 24-core machine.

Floating licenses

If you have a Linux cluster and want to make limited use of the Amsterdam Modeling Suite (AMS), a floating license may be used, which allows you to run on a limited number of cores at any time, but these may be used from any of your compute nodes having access to a central shared directory.

For example with a 16-core floating license, you can use a maximum of 16 CPU cores of the cluster at the same time, so either one 16-core job or two 8-core jobs can run concurrently. 

For our license fees, floating cores count double, i.e. a 16-core floating is the same as a 32-core host-locked license.

The GUI and COSMO-RS are always host-locked.

Floating licenses are only available on Linux and can not be used on Windows or Mac.

Mixed host-locked and floating licenses

Mixed floating / host-locked licenses are also available. The minimum number of floating cores per cluster that we allow is four (4). We only allow floating or mixed host-locked floating licenses from 8-core floating or 16-core host-locked upward. Floating cores are counted as two (2) each, host-locked cores as one (1) each.


  • Two 2-core machines and one 4-core machine together add up to (2×2 + 4) eight cores
  • A 6-core machine with hyperthreading counts as six cores. We always count physical cores (hyperthreading is not recommended anyway). Since the minimum number of cores is eight, you can license an additional dual-core machine for the 8-core license.
  • A 24-core floating license and two 8-core host-locked licenses are counted as 24×2 + 8 + 8 = 64 host-locked cores
  • A 128-core cluster can be licensed on the whole (most flexible), for specific nodes (cheapest, least flexible) or with a floating license (flexible, any nodes in the cluster may be used up to a specified number of cores)

Unlimited licenses

An unlimited license will enable all members of your own research group (or site if you purchase a site license) to install our software on their machines on the research site. With SCM’s permission, licenses may also be installed on personal machines to facilitate setting up and analyzing jobs remotely.

Unlimited licenses are also ideal for teaching purposes (at no additional cost). Students can easily download and use AMS during the course. The installation is smooth, with a set number of licenses automatically approved for the teaching account, either on the instruction machine or, with SCM’s permission, on the students personal laptops. SCM then also offers support to the system administrator for setting up AMS on the student machines, but no direct support can be given to the students.

Different modules

Starting with our 2018 release, we use module points to determine the license fees. Our 2022 release includes two new modules. You may select a specific number of cores for each module.
Any license containing one of SCM’s own modules includes the Amsterdam Modeling Suite Core: the graphical user interface, the PLAMS python scripting environment, and the central AMS driver for complex tasks on the Potential Energy Surface. It also includes some basic force fields, builder, and analysis tools.

Send us an email if it is unclear how your specific situation should be licensed. Use the online Price Quote Form to get detailed prices.

Recommended hardware

Please check out the summary from a webinar in 2020 on hardware recommendations.