In order to isolate the performance differences of Microsoft Windows Vista with different amounts of system memory, we'll be testing the following PC system with 512MB, 1GB, 2GB and 4GB of memory. While Microsoft Windows Vista will technically run with as little as 256MB of memory installed, the operating system will not allow you to install it onto a computer unless it detects 512MB RAM.

Initially, PCSTATS was going to run a series of benchmarks to guage the impact of different levels of system RAM in three versions of Microsoft Windows Vista; Home Basic, Home Premium and Ultimate. However after a few quick tests we quickly found that all three versions of the operating system perform the same. For the purposes of this article, the benchmarks will be conducted on Microsoft Windows Vista Ultimate.

The purpose of the benchmarks on the following pages is to illustrate how the PC system reacts to the various memory configurations under Vista, for office applications and games. Please note that when the system is installed with 512MB of memory, it is in single channel mode. A DDR2-800 512MB dual channel memory kit was not available for testing. To keep this as simple as possible, all memory was set to run with BIOS timings of 5-5-5-15 at DDR2-800 speeds. In other words, we've normalized the memory settings so each of the three different memory modules will operate at the same basic level.

Let's begin. First the test system configuration below, and then the first benchmark of the day - Vista's Windows Experience Index.

PCSTATS Test System Configurations

test system processor: intel Core 2 Duo E6600 Clock Speed: 9 x 266 MHz = 2.4 GHz Motherboards: Asus P5N32-E Plus (NF 650i) Videocard: MSI NX7800GTX-VT2D256E Memory: 512MB Corsair CM2X512-8500 1GB Kit Corsair Twin2X1024-8500 2GB Kit Corsair DOMINATOR Twin2X2048-8888C4DF 4GB Kit Mushkin XP2-6400 Hard Drive: 74GB Western Digital Raptor WD740 CDROM: AOpen Combo 52x PowerSupply: PC Power & Cooling TurboCool 510 SLI Heatsink: Intel Reference Software Setup: Microsoft Windows Vista Ultimate nVIDIA nForce 650i SLI 8.43 nVIDIA ForceWare 94.224 Benchmarks: Business Winstone 2004 PCMark05 3DMark06 Doom 3 FEAR

Windows Experience Index	Source: Microsoft

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.

Windows Experience Index
Memory Size Configuration:	Points	Ranking
512MB System Memory	1.7
1GB System Memory	4.5
2GB System Memory	5.3
4GB System Memory	5.3

Microsoft Windows Vista reacts strongly between 512MB and 1GB of system memory! According to Microsoft, a rating of between 1-1.9 means the system can only provide adequate performance for basic tasks. A score this low also means Vista cannot run AeroGlass if you have a compatible videocard. It's interesting to see that Windows can also tell the difference between 1GB and 2GB of memory, going from a very good score to top end. Installing 4GB of memory does not boost the overall score any further.