The Source Particle Benchmark, also known as the Multicore CPU Particle Simulation Benchmark, is a late 2006 benchmark which introduced some of the new and more advanced features of the Source engine and Valve's hybrid threading technology, such as dynamic shadows and particle-based effects, and their performance on multi-core processors. The Particle benchmark was shown at Valve Hardware Day 2006 and given out to some visitors at GDC 2007.
The Source Particle Benchmark pack consists of three folders:
The first, named "map compilation benchmark", allows to compile a map set in the Episode One Citadel, ep1_citadel_03, through the file "build_map.bat" to see how long it takes for the used computer to compile a map. As it is not to be played, the map is incomplete.
The second folder, named "particle simulation benchmark", contains the main test map, particle_benchmark, where the particle effects are showcased (to be launched with the file "particle_benchmark.bat" located in the subfolder "game"). To view them, the player has to trigger them with a button with under it the sign "Particle Benchmark", conveniently placed in the middle of the central room connected to the four other rooms, then a demo will showcase the four effects in their respective rooms. The player can also walk themself into the rooms to view the effects from different angles. When all effects have been viewed with the button, a benchmark score named "Particle Performance Metric" is displayed on the top-right of the screen. This is a representation of the amount of particles per second (in thousands) that the CPU is able to calculate.If the player has a highly equipped computer, the score will be high (more than 100, for instance). If not, the score will be low (around 35, for instance).
The map demo_blob was only shown at Valve Hardware Day 2006 and was not contained in the version handed out at GDC 2007. This map was leaked on March 24,2017 in EP1/EP2 WC Mappack. It's demonstrations of swarms of creatures interacting more realistically with the environment, doing things like avoiding dangerous areas, toppling furniture, swarming opponents, etc. The number of creatures could also be increased depending on CPU power (number of cores as well as clock speed), so where a Core 2 Quad might be able to handle 500 creatures, a single core Pentium 4 could start to choke on only 80 or so creatures.
A colored entity named "npc_surface", used to simulate dynamic liquids, can be spawned using a console command "give npc_surface". Interestingly, its model is named "Hydra.mdl", but it appears to be different and cannot be found in the files. When touched, it takes away 5 health points. Hydra textures can also be found in the texture files. According to Erik Wolpaw, the experiment behind "npc_surface" was applied to the Mobility Gels in Portal 2, with additional influence from Tag: The Power of Paint.
The third and last folder, "presentation slides", contains a PowerPoint presentation, named "multicore_hardware_day.ppt" and dated November 1st, 2006, about the new features of the Source engine, and their relation to multi-core processors. All files are dated October 27, 2006 or November 1st, 2006.