ahh, well I have to admit that I don't knew about that, and I'm not sure whether the limit still is 5.9 or not.
On the other hand, why would M$ design the 9.9 and etc.. "images" when 5.9 is the limit?
Don't know mate, I'm totally confused now
I've just found this on Windows Vista Blog
This document describes the Windows Experience Index (WEI) Model, what it is useful for, how the scores are computed, and how consumers can use it.
The Scale of the Index
The scale of the Windows Experience Index ranges from 1 to 5.9. The higher the score for a particular component area, the better experience you can expect from that area. Base Score Level
1.0 – 1.9
Basic performance. Productivity applications, IM, web, email, simple games - like Solitaire, educational games.
Minimum specification needed to run Windows Vista™.2.0 – 2.9
Improved responsiveness. Same applications as a base score of 1.0 – 1.9.
PCs will run Windows Vista but in most cases will not be Aero capable.3.0-3.9
Aero graphics, Media Center with standard definition TV, basic graphical games, basic performance while running high-end graphical games.
Minimum specification needed to run Windows Vista Premium features, including the new Aero user interface.4.0 – 4.9
Snappy performance, high definition video, high resolution monitors, dual monitors.
Very good performing PCs.
5.0 – 5.9
Fast moving games with amazingly rich graphics, 3D modeling, high-end multimedia and high performance applications.
Top end of the PC market for the Vista time frame.Base scores of 6.0 and higher are not defined yet. They will be defined when the time comes and new innovations in hardware allow new capabilities. From past experience, it is expected this will happen at a rate of once every 12-18 months.
This post was made in 2006, so it is possible that Microsoft has raised their Vista index, although I don't know why do I have "only" 5.9 index for my machine..Source..