Windows Vista and Windows 7 take better advantage of multiple cores than Windows XP, but not enough to overcome XP's greater efficiency
Windows XP SP2 outpaced Windows Vista SP1 and Windows 7 beta by leaps and bounds during multiprocess workload testing (concurrent database, messaging workflow, and multimedia tasks) on our dual-core and quad-core test beds (see main article, "The generation gap: Windows on multicore"). However, as you can see from the Scalability figures below (next page), the improvement in performance of XP when moving from dual-core to quad-core paled to the gains of Vista and Windows 7, showing that the later operating systems take better advantage of multiple cores. See "How I tested" for test details.
Windows on multicore: OfficeBench results (dual core)
Database
Messaging workflow
Windows XP
1.57 seconds
5.94 seconds
Windows Vista
3.02 seconds
11.77 seconds
Windows 7
3.42 seconds
8.18 seconds
Delta: XP to Vista
92%
98%
Delta: XP to Windows 7
118%
38%
Windows on multicore: OfficeBench results (quad core)
Database
Messaging workflow
Windows XP
0.43 seconds
4.49 seconds
Windows Vista
0.51 seconds
7.45 seconds
Windows 7
0.51 seconds
7.14 seconds
Delta: XP to Vista
19%
66%
Delta: XP to Windows 7
19%
59%
Windows on multicore: Scalability comparison
Database
Messaging workflow
Windows XP
265%
32%
Windows Vista
492%
58%
Windows 7
571%
15%
Delta: XP to Vista
86%
80%
Delta: XP to Windows 7
115%
-55%
Windows XP is more efficient
If you take the raw transaction times for the database and workflow tasks, and then factor them against the average processor utilization for these same workloads, we see that Windows XP consumes significantly fewer CPU cycles than Vista or Windows 7 to complete a single pass of the database and workflow transaction loops. XP provides a cleaner, less complex code path for the workloads to navigate as they execute, resulting in better overall performance with lower consumption of CPU cycles.
Windows on multicore: CPU cycles consumed (dual core)
Database
Messaging workflow
Windows XP
8.90 billion cycles
18.08 billion cycles
Windows Vista
12.43 billion cycles
23.54 billion cycles
Windows 7
14.93 billion cycles
25.15 billion cycles
Delta: XP to Vista
40%
30%
Delta: XP to Windows 7
68%
39%
Windows on multicore: CPU cycles consumed (quad-core)
