If you've been paying attention to the various industry news outlets you've no doubt come across the story about the Microsoft engineer advocating Windows Server 2008 as a "workstation" OS. According to him, if you make the right tweaks - installing the Desktop Experience feature, adding a few missing utilities, tuning the scheduler - you can turn Server 2008 into a fairly convincing Vista knock-off, one that's faster and more scalable than the original.
Curious, we decided to see for ourselves just how well Server 2008 stacks-up to Vista with Service Pack 1. To make the comparison as even as possible, we disabled all of the UI goodies on Vista (i.e. set the Visual Effects to "Adjust for Best Performance") and installed the Desktop Experience feature under Server 2008. We also enabled SuperFetch and the Indexing services on the Server 2008 installation (both are disabled by default) and adjusted the "Processor scheduling" option to favor Programs (i.e. the way it's set under Windows Vista).
For hardware, we reused our Dell XPS M1710 test bed (Core 2 Duo T7200 at 2GHz, 2GB RAM, 80GB 7200RPM disk) from our previous Vista testing projects. Both OS were configured to use the entire disk as a single partition, and we installed the same device drivers under each version.
The actual test scenarios involved a straight execution of the OfficeBench test script (in a 10-iteration loop) as well as a separate multi-process workload package featuring the ADO, MAPI and WMP Stress workload generation objects (executing continuously for 10 minutes in a 3x3x3 multi-instance configuration).
Given all the press surrounding Vista Service Pack 1 and the supposed parity of the SP1 and Server 2008 kernels, we were expecting to find little or no performance delta between the two platforms. So we were understandably surprised when repeated test runs showed Windows Server 2008 outperforming Windows Vista w/SP1 by a margin of 11-17%.
Clearly, there is more going on within Server 2008 than simply a few boot-time kernel switches. The very tangible performance disparity between our "Workstation" 2008 configuration and Vista, even with Service Pack 1 installed, shows that Microsoft is capable of squeezing more out of the shared "Windows 6.1" code base if/when they choose to do so.
As for what's dragging Vista down (the number of running processes and services was nearly identical across both OS and in each test scenario), that's a bit harder to define. Perhaps the Server 2008 team decided to eschew some of the more desktop-centric and/or consumer-focused (i.e. CPU cycle-sapping) features of the Vista core (DRM comes to mind). Regardless, now that we know how much better things could have been, it'll be that much harder to settle for the sluggishness and bloat of Windows Vista.
Our recommendation: If you have an MSDN account or otherwise have access to a Server 2008 license, check it out for yourself. You may find that Windows "Workstation" 2008 is the Windows Vista you've been waiting for all along.