diff --git a/dependencies/common/install-packages.orig b/dependencies/common/install-packages
index 4acca62..85eb31b 100755
--- a/dependencies/common/install-packages.orig
+++ b/dependencies/common/install-packages
@@ -107,7 +107,7 @@ fi
 
 # install packages needed to run tests
 for RPKG in purrr rmarkdown renv testthat xml2 yaml; do
-    RINSTALLCMD="if("'!'"require($RPKG, quietly = TRUE)) { install.packages('$RPKG', lib='$RPKGLIB', repos='https://cran.rstudio.com/') }"
+    RINSTALLCMD="if("'!'"require($RPKG, quietly = TRUE)) { options(Ncpus = @@proc_num@@ ); install.packages('$RPKG', lib='$RPKGLIB', repos='https://cran.rstudio.com/') }"
     echo "> $RINSTALLCMD"
     Rscript -e "$RINSTALLCMD"
 done
