It's likely the following paragraph from the Windows Help & Support section on WEI will answer your question:
'The scores currently range from 1.0 to 7.9. The Windows Experience Index is designed to accommodate advances in computer technology. As hardware speed and performance improve, higher score ranges will be enabled. The standards for each level of the index generally stay the same. However, in some cases, new tests might be developed that can result in lower scores.'
Basically newer SSD's are being released with SATA 6.0 Gbps to take advantage of higher transfer speeds, new generations of motherboards enabling these transfer speeds and improved controllers. My 160GB 34nm Intel SSD has dropped several times from 7.8 WEI score in August 2009 to a current score of 7.4. It's likely to drop further once faster SSD's are released and Windows recalibrates their WEI scores.
My issue with WEI is that I cannot find clear documentation on how each value is calculated. I am sure it is somewhere... but where? Without this, we cannot readily identify why this particular benchmark is rating your driver slightly slower.
My advice would use the Intel SSD Optimizer, reboot, disable all non-essential programs, and try again.
Otherwise, try using a better benchmarking tool.
Michael, WEI does not adjust its calcuation for newer hardware. A score should not decrease just becase faster hardware exists.
"Michael, WEI does not adjust its calcuation for newer hardware." I never said it did. If you bother to read my full post you will see the point I was making. The 'clear documentation' is never going to be there. Windows would face lawsuits from a variety of hardware manufacturers each stating the documentation is unfair if they went down that line. If users want a higher score they need to buy the fastest SSD with the fastest 6 GB/s transfer capability and a motherboard to support it. Research the WEI scores before you buy. An 80GB Intel SSD with a 3GB/s transfer rate is never going to get you a 7.9. It's always going to decrease over time as Windows raises the bar which they have to do as hardware improves. The Windows WEI score for an 80GB old generation SSD is accurate. It will reduce over time trust me.
on my systems, i disable winsat in the task scheduler (by default, it runs every week to recalculate the wei) and erase the results files. that is how much i care about wei.
the wei results are stored in .xml files, so if low numbers bother you, just edit the files to show the results you want.
Some clarification: 'As hardware speed and performance improve, higher score ranges will be enabled. The standards for each level of the index generally stay the same. However, in some cases, new tests might be developed that can result in lower scores.' Pulling a 1 year old forum post in response to this is barely sensible. An 80GB Intel SSD is not up to a 7.8 or 7.9 score under WEI. Over time the scores wil inevitably be reduced. If people want a high score, and in my experience they always want a 7.9 under WEI, they would have to update their hardware regularly. Anyone expecting their hardware to always achieve the same results under WEI is badly mistaken. An 80GB Intel SSD is undeserving of a 7.4 or above score. 7.3 sounds about right. Hopefully Intel will upgrade their SSD's soon as they are in need of a refresh.
the blog entry is just describing what ms developers had in mind with wei.
my own advice about the wei is to simply ignore it. if you believe your ssd is slowing down, there are other much better benchmarks you can use.
The WEI is actually quite a good benchmark with Win 7.
Use CMD and type "winsat disk" and a WEI benchmark will execute. You will see results for each subtest that makes up the overall WEI score.
Here is a X25-M 160 in a used state.
> Disk Sequential 64.0 Read 262.89 MB/s 7.6
> Disk Random 16.0 Read 233.82 MB/s 7.9
> Responsiveness: Average IO Rate 1.16 ms/IO 7.8
> Responsiveness: Grouped IOs 10.83 units 7.0
> Responsiveness: Long IOs 2.78 units 7.9
> Responsiveness: Overall 30.14 units 7.5
> Responsiveness: PenaltyFactor 0.0
> Disk Sequential 64.0 Write 104.95 MB/s 6.6
> Average Read Time with Sequential Writes 0.488 ms 7.9
> Latency: 95th Percentile 1.767 ms 7.8
> Latency: Maximum 281.883 ms 7.1
> Average Read Time with Random Writes 0.551 ms 7.9
> Total Run Time 00:01:07.27