diff --git a/build.sc b/build.sc
index cdfff96b9d9c1733d468cfd31075e86405c91b10..7c213135564a9d041e2024ebb1bb7acfff0d8bb8 100644
--- a/build.sc
+++ b/build.sc
@@ -81,7 +81,7 @@ object chiseltest extends CommonModule with SbtModule {
 object XiangShan extends CommonModule with SbtModule {
   override def millSourcePath = millOuterCtx.millSourcePath
 
-  override def forkArgs = Seq("-Xmx12G")
+  override def forkArgs = Seq("-Xmx20G")
 
   override def ivyDeps = super.ivyDeps() ++ chisel
   override def moduleDeps = super.moduleDeps ++ Seq(