I noticed that I should wait for Discuss pages much longer than Modx pages, so I added some tags to get debug info. Modx pages have total time 0.2-0.3 s (when they came from the cache). Discuss pages have total time 3-4 s, for example:
Total Time [^t^]: 3.4163 s
Query Time [^qt^]: 0.0518 s
Query Count [^q^]: 3,
Parse Time [^p^]: 3.3645 s
Source [^s^]: cache
Why so long? Some time ago I had the same issue on Modx pages - because I had a lot of uncached snippets [[!...]] on page. I removed exclamation marks from wherever I could, and now all works fine and quite fast. But what is wrong with Discuss? Is it a bug? But seems that
http://forums.modx.com/ loads not so fast also, but faster than 3 s anyway (considering a lot of topics!). Will it be fixed in Discuss 1.3 if it is bug? Or may be I missed something in my Discuss. Recently I had 1.1.1 and now updated to 1.2.