diff --git a/HLTrigger/Configuration/test/cmsDriver.csh b/HLTrigger/Configuration/test/cmsDriver.csh
index f8f665e2cd159..699f93e083b4a 100755
--- a/HLTrigger/Configuration/test/cmsDriver.csh
+++ b/HLTrigger/Configuration/test/cmsDriver.csh
@@ -230,10 +230,20 @@ foreach gtag ( MC DATA )
     echo "Creating DigiL1Raw $name"
     cmsDriver.py RelVal                 --step=DIGI,L1,DIGI2RAW                            --conditions=$GTAG --filein=$InputGenSim                        --custom_conditions=$XL1T  --fileout=RelVal_DigiL1Raw_$name.root    --number=$NN $DATAMC --no_exec --datatier 'GEN-SIM-DIGI-RAW'               --eventcontent=RAWSIM                  --customise=HLTrigger/Configuration/CustomConfigs.L1T     $Era --customise=$Custom  --scenario=$SCEN --python_filename=RelVal_DigiL1Raw_$name.py
 
+    cat >>RelVal_DigiL1Raw_$name.py<<EOF
+process.options.numberOfThreads = cms.untracked.uint32(1)
+process.options.numberOfStreams = cms.untracked.uint32(1)
+EOF
+
     echo
     echo "Creating DigiL1RawHLT $name"
     cmsDriver.py RelVal                 --step=DIGI:pdigi_valid,L1,DIGI2RAW,$XHLT          --conditions=$GTAG --filein=$InputGenSim                        --custom_conditions=$XL1T  --fileout=RelVal_DigiL1RawHLT_$name.root --number=$NN $DATAMC --no_exec --datatier 'GEN-SIM-DIGI-RAW-HLT'           --eventcontent=FEVTDEBUGHLT            --customise=HLTrigger/Configuration/CustomConfigs.L1THLT  $Era --customise=$Custom  --scenario=$SCEN --python_filename=RelVal_DigiL1RawHLT_$name.py  --processName=$PNAME
 
+    cat >>RelVal_DigiL1RawHLT_$name.py<<EOF
+process.options.numberOfThreads = cms.untracked.uint32(1)
+process.options.numberOfStreams = cms.untracked.uint32(1)
+EOF
+
     echo
     echo "Creating FastSim $name"
     cmsDriver.py TTbar_Tauola_13TeV_TuneCUETP8M1_cfi --step=GEN,SIM,RECOBEFMIX,DIGI,L1,DIGI2RAW,L1Reco,RECO,$XHLT --fast --conditions=$GTAG                             --custom_conditions=$XL1T  --fileout=FastSim_GenToHLT_$name.root    --number=$NN $DATAMC --no_exec --datatier 'GEN-SIM-DIGI-RECO'              --eventcontent FEVTDEBUGHLT            --customise=HLTrigger/Configuration/CustomConfigs.L1THLT  $Era --customise=$Custom  --scenario=$SCEN --python_filename=FastSim_GenToHLT_$name.py     --processName=$PNAME