The normal stats usually finish updating by the 10 minute mark, so the 20 minute mark should be safe to keep the two reasonably in sync.
Please keep in mind that the flat files should be accessed by scripts no more than 24 times a day and that the web site urls in the cgi-bin directory should not be accessed by automatic scripts (please see our robots.txt for details).
We have been tracking down a bug in our stats by operating system page and it looks like we have now found it. Basically, we were counting SMP clients as giving 1 CPU. This grossly undercounted the total number of CPUs, especially for Linux and OSX. Please note that we have only updated this particular page (stats by operating system) and are looking into updating other ones with the additional information of the number of CPUs per client.
There is a remaining known issue with under-reporting the number of NVIDIA clients. We are working on this.
For those who are curious, here's the latest as of 5 min ago:
Active CPUS are defined as those which have returned WUs within 50 days. Active GPUs are defined as those which have returned WUs within 10 days (due to the shorter deadlines on GPU WUs). Active PS3's are defined as those which have returned WUs within 15 days.