Like the previous Quake games the multiplayer has a client-server architecture. The network code has been altered from Doom 3, allowing for larger numbers of players on each server (Doom 3 has a four player restriction, whereas Quake 4 has a standard 16 player limit).
One of the changes to the network code is a move from the per-polygon hit detection system used in Doom 3 back to using hit-box system like most other online first-person shooters such as other Quake games and Half-Life. In the 1.4.x point release, these "axis aligned bounding boxes" were replaced with axis aligned octagonal "cylinder", to make the hit-boxes more representative of the model shape.
In the 1.3 point release, there is an increased amount of air acceleration in multiplayer mode, making the game feel faster than the original release. In the 1.4.1 / 1.4.2 releases, there were further changes related to the way sliding on angled surfaces worked, with the introduction of the new "power slide" code, which makes the game feel even faster.
* Pentium 4 2.0 GHz or G4 1.67 GHz CPU,
* 512 MB RAM,
* 2.8 GB hard disk space,
* sound card,
* OpenGL compatible 64 MB video card,
* Radeon 9700 or GeForce 3