I have a Centrino Duo T2300 with 1 Gig of Ram and loaded the demo version of
Offict 2007 Professional. I have a 15 Meg spreadsheet created in Excel 2003
which I loaded and saved it in Excel 2007. It has a number of graph tabs.
When I press a graph tab it takes almost 5 seconds to switch between tabs.
This was almost instantaneous on 2003. It this the expected performance. In
addition the the memory size increases significantly with each graph tab and
is currently sitting at over 400 Meg.

Spreadsheed is ~ 8300 rows of data (345 days of hourly data). The
recalculation is turned off and I need to do a simple X-Y plot of 5 variable
versus time. To get graphs by month I have copied the same chart and change
the X-Scale min/max values to show 1 month of data per Tab. the result is
each graph displays ~750 data points of the 8300 defined in the graph range.
In Excel 2003, the ability to switch tabs is "instantaneous" in Excel 2007 it
takes ~5 seconds the first time and is shorter if it is reselected. Each tab
that is selected used a significant chunch of memory.

This makes Excel 2007 unusable to me and I have removed the Office 2007
Professional Trial version and have gone back to 2003 where I'll have to stay
is this is Excel 2007's performance. For a spreadsheet that supports
1,000,000 rows, graphing of this data set should be a breeze not a
significant slowdown from 2003.