In regular use Chrome sandboxes the HTML and Javascript rendering engines, which is how it can make tabs. It is not the same as using Sandboxie or the Avast sandbox. However, I think when you go into Incognito Mode you are pretty much "sandboxed" and much safer from various exploits, but this is less user friendly than Avast's sandbox. Google bought a company called GreenBorder which made a very good sandbox software comparable to Sandboxie. I think that's where the Incognito Mode must come from. I'm not 100% sure so please forgive me for any errors.
In my travels in Internet security, the ultimate combined safety and usability comes from Chrome behind Avast's sandbox, with the downloads location, bookmarks and browsing history separated from the sandbox. I just have to be careful with what I download.
Anyway, back on topic, I bet if AV-Test.org were to test against Internet malware with Chrome sandboxed by Avast the result would be very different.
