I need to generate thousands of pdf reports, based on some data. Right now I am using pdflatex for this. Are there differences in performance between pdflatex and other TeX derivatives? My content is mainly tables, figures (TeX based code) and some text. No references, no BibTeX. Right now I need two LaTeX runs for a correct rendering. Maybe I can get down to one, if I can get rid of longtables.
Use plain TeX
One way to much faster compilations is to code in plain TeX, instead of LaTeX.
Create your own format
Another way is create your own format with only the commands you need.
Abandon TikZ/Pgf in favour of MetaPost
Furthermore, consider changing from TikZ/Pgf to MetaPost (and use LuaTeX). LuaTeX has the MetaPost library built-in. Compared to pdfTeX, LuaTeX is slower for mainly text based documents but magnitudes faster when it comes to generating documents with lots of graphics.
If these solutions can be applied to your work flow, depends entirely on your type of documents and complexity of graphics