Even during one of the biggest weeks for the Olympics on TV all 3 CSI shows top the charts of the "List of top 20 shows in prime-time Nielsen ratings" for the week August 11th to 17th 2008
With top polling positions as follows;
13th CSI Miami with 6.31 million viewers.
16th CSI: NY 5.79 million viewers.
20th CSI: Crime Scene Investigation 5.33 million viewers.
Here is the full list showing CSI in prime time Nielsen Ratings