diff --git a/sims/vcs/vcs.mk b/sims/vcs/vcs.mk
index 9913481c..3876a43d 100644
--- a/sims/vcs/vcs.mk
+++ b/sims/vcs/vcs.mk
@@ -36,6 +36,7 @@ VCS_CC_OPTS = \
 	$(filter -l%,$(VCS_LDFLAGS))
 
 VCS_NONCC_OPTS = \
+	-j36 \
 	-notice \
 	-line \
 	+lint=all,noVCDE,noONGS,noUI,noPCTIO-L,noPCTI-L \
diff --git a/sims/verilator/Makefile b/sims/verilator/Makefile
index d90c4c38..12c793b0 100644
--- a/sims/verilator/Makefile
+++ b/sims/verilator/Makefile
@@ -195,13 +195,13 @@ model_mk_debug = $(model_dir_debug)/V$(TB).mk
 $(model_mk): $(sim_common_files) $(EXTRA_SIM_REQS)
 	rm -rf $(model_dir)
 	mkdir -p $(model_dir)
-	$(VERILATOR) $(VERILATOR_OPTS) $(EXTRA_SIM_SOURCES) -o $(sim) -Mdir $(model_dir)
+	$(VERILATOR) -j 36 $(VERILATOR_OPTS) $(EXTRA_SIM_SOURCES) -o $(sim) -Mdir $(model_dir)
 	touch $@
 
 $(model_mk_debug): $(sim_common_files) $(EXTRA_SIM_REQS)
 	rm -rf $(model_dir_debug)
 	mkdir -p $(model_dir_debug)
-	$(VERILATOR) $(VERILATOR_OPTS) +define+DEBUG $(EXTRA_SIM_SOURCES) -o $(sim_debug) $(TRACING_OPTS) -Mdir $(model_dir_debug)
+	$(VERILATOR) -j 36 $(VERILATOR_OPTS) +define+DEBUG $(EXTRA_SIM_SOURCES) -o $(sim_debug) $(TRACING_OPTS) -Mdir $(model_dir_debug)
 	touch $@
 
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