The Windows Vista Windwos Experience Index Score never made much sense to me. It grades a PC on 5 factors and then chooses the lowest score as the index. No weighting, no average, just what looks like a poorly thought out implementation of some kind of over simplified Fuzzy Logic. Since the graphics subsystem is generally the weakest component (unless you are a serious gamer), it generally defines the score for the entire system.
I finally got around to upgrading my old Athlon 64-bit 3400+ based PC from 1GB to 2GB RAM. This PC doesn’t have a dedicated graphics card, but the integrated chipset is the Nvidia GeForce 6100 which isn’t too shabby as built-in graphics goes. It uses shared RAM and Vista decided that it had 831MB of available graphics RAM after the upgrade. This was enough to boost the Graphics index from 2.0 to 3.0 and thus raise the entire index score from 2 to 3 as well.
The interesting thing is that the Dell Latitude D620 notebook PC (running Windows Vista Business Edition) with its Core 2 Duo and a dedicated graphics adapter with dedicated graphics score in reduced performance battery saving mode less than this old single core PC of mine because of Microsoft’s scoring quirk. In this case the CPU performance in battery saving mode becomes the weakest component in the score (less than the graphics adapter). The end result is that an aging single core CPU based PC score higher than a Core 2 Duo based one. That just doesn’t sit will with me. And, I don’t think the actual end-user experience matches the scores either.