diff --git a/GNUmakefile b/GNUmakefile
index b9151dd25a..6e58efd832 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -2,7 +2,7 @@ AGDA_BIN?=agda
 AGDA_FLAGS?=-W error
 AGDA_EXEC?=$(AGDA_BIN) $(AGDA_FLAGS)
 FIX_WHITESPACE?=fix-whitespace
-RTS_OPTIONS=+RTS -H3G -RTS
+RTS_OPTIONS=+RTS -H6G -RTS
 AGDA=$(AGDA_EXEC) $(RTS_OPTIONS)
 RUNHASKELL?=runhaskell
 EVERYTHINGS=$(RUNHASKELL) ./Everythings.hs