Update speed.rst

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diff --git a/doc/articles/speed.rst b/doc/articles/speed.rst
index 9962c07f..81af5a23 100644
--- a/doc/articles/speed.rst
+++ b/doc/articles/speed.rst
@@ -81,6 +81,10 @@ If the background is low and/or smooth, you can use the faster ``zaef`` peak
 search algorithm instead of ``peakfinder8`` without compromising on the
 results.
 
+The speed of ``peakfinder8`` can be improved with option ``indexamajig
+--peakfinder8-fast``, which tells CrystFEL to pre-calculate some structures.
+This is only possible with a static detector geometry (see below).
+
 
 Choose the fastest indexing algorithms
 ======================================
@@ -134,6 +138,22 @@ improvement.  However, the ``--push-res`` value that you use for merging must
 be smaller than the value used for integration.
 
 
+Don't need integration results?  Don't integrate!
+=================================================
+
+If you're using CrystFEL as part of an online monitoring system, you might not
+be interested in the integration results at all.  Since spot prediction and
+integration can take a significant amount of time, you can save a lot by
+disabling them.  Disable integration, but not prediction, with ``indexamajig
+--integration=none``.  The stream will contain predicted spot positions, but
+their intensities will all be zero.  Disable prediction altoghether with
+``indexamajig --cell-parameters-only``.
+
+This is particularly important when doing "unrestricted" indexing with no
+prior unit cell information.  Occasional spuriously large unit cells can slow
+things down a lot by producing a lot of reflections.
+
+
 Use a static detector geometry
 ==============================