Windows Experience Index: an indepth look

Message Topic Search Topic Options Post Reply Create New Topic Printable Version

For Windows Vista™
Introduction
The
Windows® Experience Index is a new feature built into Windows Vista™.
It is designed to help consumers understand how well Windows Vista and
the software running on it will perform on a specific PC. The index
achieves this by assessing the capability of the PC and assigning a
score to it. Higher scores indicate a better Vista experience on your
PC. 
The
overall PC performance is represented by the base score. The base score
is derived from 5 subscores for each of the following 5 attributes:

•  Processor

Calculations per second

•  Memory

Operations per second

•  Graphics

Desktop performance for Windows Aero graphics

•  Gaming graphics

3D graphics performance. Useful for gaming and 3D business applications

•  Primary hard disk

The data transfer rate of the primary hard disk
The Windows Experience Index is useful for the following:
1.      When buying a new PC, it is useful for determining the quality of the Windows experience a buyer can expect from a particular PC.
2.      When upgrading a PC,
the index is useful for estimating the overall improvement a PC user
can expect to get when replacing or adding a new hardware component. 
3.      When buying software,
the software package may include the recommended Windows Experience
Index base score a PC should have in order to run the particular
software application well.  If a PC has a higher base score than the score recommended by the software, the software will run well on it.
About This Document
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. 
The
scale is useful when comparing hardware components and when comparing
whole PCs. The scale was created so that a full score point of
improvement usually means significant additional capabilities in the
particular sub area, while a better fractional score means an
incremental improvement. The integer number of a base score is referred
to as the Windows Experience Index level. For example a PC with a
Windows Experience Index base score of 5.3 is considered a level 5 PC.
Over
time, as systems become more advanced, we expect to introduce higher
levels of 6 and beyond. This will be done approximately every 12-18
months, as new innovations in hardware become available. When new base
scores are introduced, existing scores will not change (i.e. a PC with
a base scored of 2.2 today will score a 2.2 in the new updated index,
unless its components are upgraded).

Base score definitions

Each
base score level defines an improved experience over lower levels. A PC
will work well running scenarios of its level in addition to scenarios
of lower levels.
The base score levels at a glance: 

Base Score Level

Applications and Scenarios

Description

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.

A base score of 6 and greater will be defined when new hardware innovations reach the market.
The following are detailed descriptions of each of the base score levels:

 1.0

A base score of 1.0 is intended to reflect the minimum specification needed to run Windows Vista™.  PCs
that meet this level will run Windows Vista™ in a basic, but acceptable
manner. This is a “catch all” level assigned to any machine that can
realistically be upgraded to Windows Vista™ but won’t meet level 2
specifications.

 2.0

A
base score of 2.0 represents the mainstream Windows Vista upgrade
target system. This level of PC may run Windows Aero but users may see
noticeable performance issues from time to time, especially on PCs with
base scores less than 2.5 and/or 64MB of graphics memory. Performance
issues may also be noticeable when opening many application windows at
the same time or when using very large monitors.

 3.0

This
is the lowest capability Windows Premium Logo PC that will ship with
Windows Vista™ pre-installed. Windows Vista will generally enable Aero
automatically on level 3 machines.  Aero will perform quite well on level 3 machines with single monitors.  With
dual monitors (especially larger than 1280x1024), users may see
noticeable performance issues from time to time, especially on PCs with
base scores less than 3.5 and/or 128MB of graphics memory. 

4.0

All Windows Vista features will run well with snappy performance.  HD playback and recording of one HD stream will work well.  3D games and other high-end 3D applications will run acceptably on Level 4 machines.  Multi-tasking
will be quite good on these machines (when an application makes use of
this capability). Many mid to high level 4 PCs will have dual core CPUs.

5.0

Level
5 PCs will dramatically exceed the Windows Premium logo requirements.
They will easily run Aero-Glass on multi-monitor systems at high
resolution.  First person shooters, multiple HD
streams, video creation, high end multimedia applications are all
characteristic scenarios of people who will be using Level 5 systems.  As
Level 6 machines are not defined yet, it is possible that the highest
performance and capable Level 5 machines may be re-leveled as level 6
in the future (i.e. that may happen if the new hardware is evaluated
before the index is updated with the new capabilities).

6.0

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.

Computing the Base Score
The
Windows Experience Index score – often called the base score – is
always a decimal value greater than zero. E.g. the base score is a
number like 3.6 or 5.6.
Since
a system’s performance is limited by its slowest component, the final
system base score is the lowest value of the five subscores. In the
example below, the WEI base score is 3.8 and is determined by the
processor’s score of 3.8.   

Note: The model logic is tolerant of one subscore being below the threshold for a particular level by 0.1.  For example, assume that in the above example, the memory score was 4.0 and the processor score 3.9.  This
would mean that the processor score would marginally be the only item
keeping the base score below level 4. The model addresses this issue by
rounding up a single value that is below the next round level by 0.1. 

Computing Each Subscore 
Each sub score in
the index was created to measure the performance of a critical piece of
hardware. The scores are calculated by measuring one or more relevant
performance attributes, and then converting the values (normalizing) to
a score between 1.0 and 5.9.
In this section you can read what is tested for each subscore.

The CPU Score
The
CPU score was created to measure the processor performance when tasked
with common Windows usage activities. The processor is assessed on the
following items:

1.      Compression and decompression using the LZW compression algorithm
2.      Compression
and decompression using the Windows Vista compression algorithm used
for hibernation files, ReadyBoost and other features
3.      Encryption and decryption assessment
4.      Computing hashes
5.      Encoding of video
The results are normalized and weight averaged in order to arrive at the final CPU sub score.
The Memory Score
The memory score
measures the bandwidth of moving data into and out of memory in Mega
Bytes per Second. The higher the bandwidth, the better the memory.  
Not having enough
memory is a limiting factor on performance. As a result, the amount of
memory in the system constrains the score value. The amount of system
memory is determined by the overall system memory minus any memory
reserved for graphics (if any). 
 The amount of memory limits are: 

Amount of memory

Highest possible score

Less than 256 MB

1.0

Less than 500 MB

2.0

512 MB or less

2.9

Less than 704 MB

3.5

Less than 960 MB

3.9

Less than 1.5 GB

4.5
The Graphics Score
This score is
intended to reflect how a system will run Aero (desktop composition)
and playback Windows Media Video. It measures video memory bandwidth
(in mega bytes per second) and converts it to a score between 1.0 and
5.9.
If the graphics
hardware does not support DirectX 9 (DX9) graphics, then the system
receives a graphics score of 1.0 regardless of driver type. If the
system supports DX9, but does not have a WDDM Driver (Windows Vista
Display Driver Model) the system will then receive a graphics score of
1.9 at the most.
The Gaming Score
The gaming score measures the frames per second the graphics card can handle for various textures. 
Additional notes:
·        If the graphics card does not support D3D 9 then it receives a Gaming score of 1.0.
·        If D3D 9 is supported, the card is DX9 capable and has a WDDM driver, it will score at least 2.0.
·        If
the score is greater than or equal to 5.0 and the graphics sub-system
does not support Pixel Shader 3.0 then the score is limited to 4.9
The Disk Score
The disk score
measures disk bandwidth (in Mega Bytes per Second). The conversion to
an index number is set up in a way that all modern disks will score at
least 2.0.
Using the Windows Experience Index
The
Windows Experience Index is very useful for consumers when buying a new
PC, when upgrading an existing PC and when buying new software. This
section explains how the index can be used in each of these situations. 
When Buying a New PC
When buying a new PC
a customer is usually confronted with the dilemma of which PC to
choose. A PC’s value is multi-dimensional. The value is a collection of
many attributes including performance, industrial design, noise, size,
weight, power consumption, connectors, capacity of disk & memory,
peripherals (DVD burner, etc.), networking, included software, and
more. The most difficult aspect to understand is how well the PC will
perform when running Windows and other software and the type of
experience you can expect. The only way to do this today is to look at
a long and arcane list of technical terms and try to figure out what
the combination of them would mean when running Windows. This is very
difficult to do, even for the most experienced customers.
This is where the Windows Experience Index comes in. It can help you while shopping for a new PC: 
1.      First, determine the base score level of PC you are looking for. This can be done using the “base score levels table” on page 4.
2.      Second,
look for PCs with that base score level or higher. For example, if you
determined you need a PC with a base score of 3.0, look for PCs at
level 3.0 and above.
3.      To
determine which PC to buy, look at all the additional characteristics
each PC provides and determine which package if the right one for you.
4.      To
compare the experience you can expect to get from 2 different PCs, you
can check their WEI base scores as well as their subscores for each of
the five areas.
When Upgrading a PC
The WEI score is
very useful when upgrading a PC. The following examples illustrate how
the WEI score can be used when considering an upgrade.
Ordering upgrades directly from the PC manufacturer
Rachel, a PC user
decides to upgrade her PC after starting to view videos and editing
photos on it. She goes into “Performance Information and Tools” from
the control panel. Her system rating shows a WEI base score of 2.1. She
has determined that a base score of 3.0 or greater is sufficient for
her needs.

On
the bottom, next to the logo of the PC manufacturer, Fabrikam, she
notices the following link: “View ways to increase your rating”. After
clicking it, she is directed to the Fabrikam web site which suggests a
few upgrade options for her. She chooses the components she is
interested in and is given directions for a self upgrade or for sending
her PC in for the upgrade to level 3. Note: This link will be provided
by certain PC manufactures that offer upgrades.
Manually Upgrading a PC
Consider a customer who owns the following PC:

Processor

4.7

Memory (RAM):

2.9

Graphics:

4.3

Gaming graphics:

4.2

Primary hard disk:

4.1
The
customer has recently bought a digital camera and is now using the PC
with many more programs running concurrently. Due to the added load on
the PC, the customer feels the PC is less responsive than it used to
be. He thus goes into “Performance Information and Tools” in the
control panel to try to discern how to improve the PC performance.
Looking at the WEI results presented there, it is clear that the base
score of the PC is significantly impacted by the memory score which is
by far the lowest score. To improve performance, it seems that adding
more memory or putting in faster memory if possible would be the method
of choice for improving performance.  Checking
the amount of memory in the PC by clicking on the “View and print
details”, the customer discovers that the PC has only 512MB of RAM
available. This indicates that the low memory score is probably due to
lack of memory. The conclusion would be to check if the PC can support
more memory and upgrade it.  
Consider this second PC:

Processor

5.5

Memory (RAM):

5.3

Graphics:

3.1

Gaming graphics:

3.0

Primary hard disk:

5.1

This
customer has recently bought a new game. The game works well on this PC
but is throttled back due to lack of performance by the PC. The
customer decides to take a look at the WEI score by going into
“Performance Information and Tools” in the control panel. Looking at
the scores, it is apparent that this PC could benefit from an upgrade
of the graphics card. The customer walks into a computer retail store
and looks for a graphics card with a manufacturer recommended component
subscore of 5.0 or higher on it. The customer ends up buying a Fabrikam
series graphics card and upgrading his/her PC. After the upgrade, the
new game graphics are smoother and have additional lighting effects.
When looking at the WEI scores after the upgrade, the customer notices
the new PC score has changed from 3.0 to 5.1. 

The new score is the following: 

Processor

5.5

Memory (RAM):

5.3

Graphics:

5.3

Gaming graphics:

5.6

Primary hard disk:

5.1
The new base score is now determined by the primary hard disk subscore, which is now the lowest of the subscores.

When Buying Software

When
buying software, knowing your PC base score is very useful. With it you
can determine if the software you are buying will run well on your PC.
Microsoft is working with software vendors to use the base score and
subscores for recommended system requirements. We expect to have some
software vendors using it at the time of Windows Vista launch and many
more following the launch.
When
determining if your PC can run a specific software package, look for
the system requirements section on the retail product packaging. The
recommended WEI score is the base score the software vendor recommends
your PC should have to get an adequate experience when running this
software application. The packaging may also include a minimum WEI base
score which would indicate the minimum performance a PC should have to
be able to run the application. Example: 

Summary
The
Windows® Experience Index is a new feature built into Windows Vista™.
It can considerably help consumers understand how well Windows Vista
will perform on a specific PC, and make the buying process of new PCs,
hardware upgrades, and software simpler. 
The following topics about the Windows® Experience Index were covered in this document:
1.      Description of the Windows Experience Index
2.      How the scores are calculated
3.      How the index can be used in the following cases:

a.      When buying a new PC
b.      When upgrading a PC
c.       When buying software

Edited by skyR - 22 Oct 2007 at 7:00pm

Windows Experience Index: an indepth look

About This Document

Base score definitions

Computing the Base Score

Computing Each Subscore

The CPU Score

The Memory Score

The Graphics Score

The Gaming Score

The Disk Score

Using the Windows Experience Index

When Buying a New PC

When Upgrading a PC

Ordering upgrades directly from the PC manufacturer

Manually Upgrading a PC

When Buying Software

Summary

About Us

Community

Support

Company

Contact Us

Follow Us