Why does chromium open 5 differents chrome.exe processes when starting?

Question

In my process explorer, when I launch chromium, I see 5 chrome.exe processes. How is it possible ? I though it opened a chrome.exe process per tab, but at start, my chromium window has only 1 tab.

Solution

Chromium uses one process per plugin, one process per renderer (which corresponds to the number of tabs, generally speaking), and another browser process to manage all of the renderers. The renderers each run in their own sandboxes and can't directly use your disk, network, or display, which they must request access to through the browser process so that they can be monitored for suspicious activity.

Comments

[Admin]

Also, just like to point out that this is a "good thing" and that the Windows task manager overcounts the memory of each process, as much is shared between them.

[Arjan]

And Chrome might also be updating the list of known bad websites, and be checking for other updates. I am not sure if that shows as a different chrome.exe process though, or is part of the main process.

[TomOnTime]

To be clear why this is a good thing: Each process runs in in a way that is isolated so that if something bad happens, only that process is affected. That is, if someone discovers a security hole triggered by (for example) sending funny HTML, only that renderer will be affected and it can't affect the other processes, and most likely can't escape to attack your computer. Also, it provides crash protection. If there is a bug and one renderer or plugin dies, Chrome can kill that one thing; which is better than having to kill all the windows.