diff --git a/.circleci/run.sh b/.circleci/run.sh
index f662364a7a..2636efee49 100755
--- a/.circleci/run.sh
+++ b/.circleci/run.sh
@@ -151,7 +151,7 @@ coverage()
 
     cp $build_path/dmd _${build_path}/host_dmd_cov
     make -j1 -C src -f posix.mak MODEL=$MODEL HOST_DMD=../_${build_path}/host_dmd_cov ENABLE_COVERAGE=1 PIC="$PIC" unittest
-    make -j1 -C test MODEL=$MODEL ARGS="-O -inline -release" DMD_TEST_COVERAGE=1 PIC="$PIC"
+    DMD_TESTSUITE_MAKE_ARGS=-j3 make -j1 -C test MODEL=$MODEL ARGS="-O -inline -release" DMD_TEST_COVERAGE=1 PIC="$PIC"
 }
 
 # Checks that all files have been committed and no temporary, untracked files exist.
diff --git a/appveyor.sh b/appveyor.sh
index 5faa60f1b9..39e6bdbc35 100644
--- a/appveyor.sh
+++ b/appveyor.sh
@@ -82,4 +82,4 @@ export MODEL="64"
 export MODEL_FLAG="-m64"
 
 cd /c/projects/dmd/test
-../../gnumake/make -j3 all MODEL=$MODEL ARGS="-O -inline -g" MODEL_FLAG=$MODEL_FLAG LIB="../../phobos;$LIB"
+DMD_TESTSUITE_MAKE_ARGS=-j3 ../../gnumake/make -j1 all MODEL=$MODEL ARGS="-O -inline -g" MODEL_FLAG=$MODEL_FLAG LIB="../../phobos;$LIB"
diff --git a/appveyor.yml b/appveyor.yml
index 9d0cd07299..12538374b7 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -79,6 +79,7 @@ build_script:
   - make -f win64.mak MODEL=32mscoff DMD=..\dmd\generated\Windows\Release\Win32\dmd.exe VCDIR="%VCINSTALLDIR%." "CC=\"%VCINSTALLDIR%/bin/cl.exe\"" SDKDIR=unused
   - cd c:\projects\dmd\test
   - set CC=c:/"Program Files (x86)"/"Microsoft Visual Studio 14.0"/VC/bin/cl.exe
-  - ..\..\gnumake\make -j3 all MODEL=32mscoff ARGS="-O -inline -g" "OS=win32" DMD=..\generated\Windows\Release\Win32\dmd.exe LIB="../../phobos;%LIB%" RESULTS_DIR=test_m32mscoff
+  - set DMD_TESTSUITE_MAKE_ARGS=-j3
+  - ..\..\gnumake\make -j1 all MODEL=32mscoff ARGS="-O -inline -g" "OS=win32" DMD=..\generated\Windows\Release\Win32\dmd.exe LIB="../../phobos;%LIB%" RESULTS_DIR=test_m32mscoff
 
 test_script: true
diff --git a/ci.sh b/ci.sh
index 9168586859..1f2b041b57 100755
--- a/ci.sh
+++ b/ci.sh
@@ -86,9 +86,9 @@ test() {
 test_dmd() {
     # test fewer compiler argument permutations for PRs to reduce CI load
     if [ "$FULL_BUILD" == "true" ] && [ "$OS_NAME" == "linux"  ]; then
-        make -j$N -C test MODEL=$MODEL # all ARGS by default
+        DMD_TESTSUITE_MAKE_ARGS=-j$N make -j1 -C test MODEL=$MODEL # all ARGS by default
     else
-        make -j$N -C test MODEL=$MODEL ARGS="-O -inline -release"
+        DMD_TESTSUITE_MAKE_ARGS=-j$N make -j1 -C test MODEL=$MODEL ARGS="-O -inline -release"
     fi
 }