Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have an Alienware M17x with an Intel Core 2 Duo P8600 2.4 GHz w/ 3 MB Cache. When I received it, it had Vista and a 5+ processor rating in the Windows Experience Index. I reformatted the hard drive and installed Windows 7. I've loaded all the drivers I can get from Dell, and now when I re-run the score all my numbers seem good except for the processor: it's now a 3.2.

What driver could I be missing that would affect the CPU performance so drastically like that? Is there a setting somewhere that is default to "run CPU at half speed" or something like that?

I checked the power states, and while plugged in the Minimum Performance is set to 5%, the max is 100%, and the cooling is Active, so the fan will turn on before the CPU decreases its speed. The fan never came on during the test.

share|improve this question

Although your PC ranked tops on Windows Vista’s scale, several things could be responsible for it not reaching the top of Windows 7’s scale:

Drivers. Manufacturers tweak their drivers with each release of Windows, and it’s possible one of your PC’s parts is still using a beta driver. When a newer driver arrives that’s optimized for Windows 7, your PC might earn a higher score.

Laptop. Your PC may be top-of-the line, but it’s a laptop, and laptops can never compete with top-of-the-line PCs. Today’s more powerful desktop PCs might have nudged your laptop out of the top ranks and into a slightly lower ranking.

Age. Microsoft designed the Windows Experience Index to change constantly over the years, adjusting for newer PCs and their faster performance. What ranked at the top of the scale last year probably won’t rank at the top of the scale in Windows 7.


you cannot compare the WEI scores in Vista and Windows 7. this is like running PCMark 03 and PCMark Vantage and then wondering why the graphics card is performing so poor with the latter. if you want reliable results for accurate comparisons , run a decent CPU benchmark test on both systems (e.g. GeekBench).

share|improve this answer
I received this computer 3 days ago. I would like to know what drivers affect the CPU performance. – Nathan DeWitt Dec 12 '09 at 22:23
Vista's Experience Index is 3 years old, Windows 7 is new, processors that scored top ratings in Vista are now only mediocre. it's an entirely different rating system, you cannot compare the two. – Molly7244 Dec 12 '09 at 22:57
See my answer for the problem. It went from 3.2 to 5.2 when I got the proper drivers installed. – Nathan DeWitt Dec 13 '09 at 18:19
up vote 0 down vote accepted

I found a set of drivers that were not installed correctly, and I was experiencing a large amount of System Interrupts, using roughly 30% CPU time. Once I got the proper drivers installed, I reran the performance benchmarker in Windows, and now my Processor rating is 5.2.

share|improve this answer
as eplained in my answer :) yet, you still cannot compare the different scores, if you want exact and reliable results, you should run the same version of a CPU benchmark program on both OS, WEI is a very basic benchmark test, lacking the accuracy required for in-depth comparison. – Molly7244 Dec 13 '09 at 18:28
thanks Molly. You were addressing the larger issue of comparing benchmarks from one OS to another. I was looking more for my particular issue of driver problems affecting CPU performance. – Nathan DeWitt Dec 13 '09 at 22:13

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.