I'm looking at a Physical Disk\Avg. Disk sec/Transfer counter in perfmon. We've always had faith in the Average number that perfmon reports over the selected time span.
I can't figure out why if I use perfmon to save the data to .csv, or relog the whole blg to .csv the number calculated by '=Average(A:A)' in excel is wildly different than the number reported in the tool. Several people seem to have asked this question in various forums over the years, but I see no answers. Specifically, the Average Avg. Disk sec/Transfer as reported in the perfmon tool is .041, but =AVERAGE(SY:SY) (this is the SY column that contains this data, PhysicalDisk(2 T:)\Avg. Disk sec/Transfer) returns 0.008787746. That's not even in the same ballpark. I even tried an AverageIf to exclude columns with a value of 0...barely makes a difference.
BTW - The counters are being recorded on a Server 2003 32bit machine and analyzed on a Win 7 64 bit machine.