I see from http://msdn.microsoft.com/en-us/library/aa140060(v=office.10).aspx that data throttle value for Excel 2002 is 2 seconds. but I can't find the default value for Excel 2003, 2007 & 2010. I assume they are 2 seconds, too. But just want to know for sure. thanks
You can check the value two ways, either via the registry:
HKCU\Software\Microsoft\Office\14.0\Excel\Options\RTDThrottleInterval
[replace the 14.0 with your office version]
..or via the Immediate window in Excel's VBA editor:
? Application.RTD.ThrottleInterval
I get 2000ms in Office 2010.