compile the same project several times get several different timing results, why?

--- Quote Start ---

Compiling from a given set of files with a given seed on a given platform is supposed to give the same results each time.

--- Quote End ---

I have also noticed random results starting in Quartus 11.1sp1 or so. In the Qsys PCIe tests in this thread:

http://www.alteraforum.com/forum/showthread.php?t=35678

Quartus 11.0 gives the same number of resources each synthesis run, whereas 11.1sp1 and 11.1sp2 give different results. Synthesis scripts in the project zip file can be used to regenerate the designs.

I agree that this is an annoying feature. The whole point of having the seed is so that the user can choose when to randomize the synthesis.

Cheers,

Dave