diff --git a/gui_windows.go b/gui_windows.go
index a8e8968..0918889 100644
--- a/gui_windows.go
+++ b/gui_windows.go
@@ -3,6 +3,7 @@
 package main
 
 import (
+	"os"
 	"strings"
 
 	"github.com/unxed/vtui"
@@ -12,6 +13,14 @@ func RunGui(backend string) error {
 	if backend == "qt" || strings.HasPrefix(backend, "ext:") {
 		return RunExternalUIWithMapping(backend)
 	}
+	// DX12: use naga DXIL backend instead of HLSL→FXC
+	// to avoid 2-6s shader compilation via d3dcompiler_47.dll
+	if os.Getenv("GOGPU_DX12_DXIL") == "" {
+		api := os.Getenv("GOGPU_GRAPHICS_API")
+		if api == "" || strings.EqualFold(api, "dx12") || strings.EqualFold(api, "d3d12") || strings.EqualFold(api, "directx") {
+			os.Setenv("GOGPU_DX12_DXIL", "1")
+		}
+	}
 	return vtui.RunInGUIWindow(100, 30, backend, func() {
 		SetupUI()
 	})