Round 5: Performance
Windows Vista is a bloated pig of an operating system. In fact, compared to Windows XP with Service Pack 2 or 3, Vista requires roughly twice the hardware resources to deliver comparable performance. Even stripped to the bone, with every new UI enhancement turned off and every new background service disabled, Vista is a good 40 percent slower than XP at a variety of business productivity tasks.

The above is no generalization. I've run the tests (repeatedly). I have the hard numbers. (You can see the full range of my results at exo.performance.network, or take in a quick snapshot of Vista/Office 2007 versus XP/Office 2003 results here; see the Test Center Daily for info on the Clarity Studio OfficeBench test script I used for these tests.) Upgrading a user from Windows XP to Vista, without upgrading their hardware, is tantamount to crippling their PC. Think of users with torches lining up outside your datacenter. It's not a pretty picture.

So just wait for the next hardware upgrade cycle and hit them with Vista then, right? Maybe. But consider this: For every CPU cycle wasted bringing Vista's bloated image on par with XP's, you could be providing your users with an actual performance increase across their core applications. If there were some compelling reason to run Vista over XP – a quantum leap in usability or manageability – I could see why the investment might be worth it. But upgrading hardware just to maintain the status quo seems silly.

Decision: Would you rather throw new hardware cycles at offsetting Microsoft's code bloat and voracious appetite for CPU bandwidth, or at a tangible, measurable improvement in application throughput and user productivity? Enough said.

Round 1: Security
Round 2: Manageability
Round 3: Reliability
Round 4: Usability
Round 5: Performance
Round 6: Hardware compatibility
Round 7: Microsoft software compatibility
Round 8: Third-party software compatibility
Round 9: Developer tools support
Round 10: Future-proofing