.. _performance:

Performance
===========

Speed benchmarks
----------------

The simulation speed of *ACEMD* was benchmarked against several systems at typical production conditions on different GPU devices.
The GPU devices were operating under sustained load.
The speed is measured in ns/day.

+-------------------------------+-------------+---------------------------------+
| Device                        | Force field | System                          |
|                               |             +-----------+----------+----------+
|                               |             | DHFR      | FactorIX | STMV     |
+===============================+=============+===========+==========+==========+
| `NVIDIA GeForce GTX 1080`_    | AMBER       | 500       | 120      | 6.86     |
|                               +-------------+-----------+----------+----------+
|                               | CHARMM      | 467       | 116      | 7.48     |
+-------------------------------+-------------+-----------+----------+----------+
| `NVIDIA GeForce GTX 1080 Ti`_ | AMBER       | 623       | 180      | 9.94     |
|                               +-------------+-----------+----------+----------+
|                               | CHARMM      | 600       | 163      | 10.7     |
+-------------------------------+-------------+-----------+----------+----------+
| `NVIDIA GeForce RTX 2080 Ti`_ | AMBER       | 1040      | 313      | 15.4     |
|                               +-------------+-----------+----------+----------+
|                               | CHARMM      | 979       | 296      | 17.0     |
+-------------------------------+-------------+-----------+----------+----------+
| `NVIDIA GeForce RTX 3090`_    | AMBER       | 1308      | 434      | 22.4     |
|                               +-------------+-----------+----------+----------+
|                               | CHARMM      | 1258      | 416      | 25.1     |
+-------------------------------+-------------+-----------+----------+----------+
| `NVIDIA GeForce RTX 4090`_    | AMBER       | 1810      | 777      | 59.2     |
|                               +-------------+-----------+----------+----------+
|                               | CHARMM      | 1772      | 711      | 58.4     |
+-------------------------------+-------------+-----------+----------+----------+


.. _NVIDIA GeForce GTX 1080: https://www.nvidia.com/en-us/geforce/products/10series/geforce-gtx-1080/
.. _NVIDIA GeForce GTX 1080 Ti: https://www.nvidia.com/en-us/geforce/products/10series/geforce-gtx-1080-ti/
.. _NVIDIA GeForce RTX 2080 Ti: https://www.nvidia.com/en-us/geforce/graphics-cards/rtx-2080-ti/
.. _NVIDIA GeForce RTX 3090: https://www.nvidia.com/en-us/geforce/graphics-cards/30-series/rtx-3090/
.. _NVIDIA GeForce RTX 4090: https://www.nvidia.com/es-es/geforce/graphics-cards/40-series/rtx-4090/

The input files for the benchmark systems can be downloaded :download:`here <./acemd_benchmarks.zip>`

Simulation systems:
    - DHFR (`Dihydrofolate reductase <https://en.wikipedia.org/wiki/Dihydrofolate_reductase>`_)
        - Number of atoms: 23,558
        - Box size: 62.23 Å ✕ 62.23 Å ✕ 62.23 Å
    - FactorIX (`Factor IX <https://en.wikipedia.org/wiki/Factor_IX>`_)
        - Number of atoms: 90,906
        - Box size: 142.09 Å ✕ 83.34 Å ✕ 78.68 Å
    - STMV (`Satellite tobacco mosaic virus <https://en.wikipedia.org/wiki/Satellite_tobacco_mosaic_virus>`_)
        - Number of atoms: 1,067,095
        - Box size: 221.2 Å ✕ 223.2 Å ✕ 224.5 Å

Simulation conditions:
    - Force field:
        - `AMBER ff99SB <http://ambermd.org/AmberModels.php>`_ or
          `CHARMM 36 <https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.23354>`_
        - `TIP3P <https://aip.scitation.org/doi/10.1063/1.445869>`_
    - Electrostatic interactions:
        - Particle-mesh Ewald (PME)
        - Grid spacing: <1.0 Å
        - Real-space cutoff: 9.0 Å
    - van der Walls interactions:
        - Cutoff: 9.0 Å
        - Switch function: none for AMBER or 7.5 Å for CHARMM
    - Constraints:
        - Constrained hydrogen bonds
        - Rigid water
        - Constraint tolerance: 1.0e-6
    - Integrator and thermostat:
        - Time step: 4.0 fs
        - Temperature: 298.15 K
        - Friction: 0.1 ps^-1
        - Hydrogen mass: 4.0 a.u
    - Output:
        - Trajectory period: 100 ps (25000 steps)