diff --git a/Makefile b/Makefile
index a72b4bc4..61dc2237 100755
--- a/Makefile
+++ b/Makefile
@@ -84,6 +84,13 @@ endif
 
 # Detect the architecture
 ifeq ($(YQ2_OSTYPE), Windows)
+ifdef MINGW_CHOST
+ifeq ($(MINGW_CHOST), x86_64-w64-mingw32)
+YQ2_ARCH ?= x86_64
+else # i686-w64-mingw32
+YQ2_ARCH ?= i386
+endif
+else # windows, but MINGW_CHOST not defined
 ifdef PROCESSOR_ARCHITEW6432
 # 64 bit Windows
 YQ2_ARCH ?= $(PROCESSOR_ARCHITEW6432)
@@ -91,6 +98,7 @@ else
 # 32 bit Windows
 YQ2_ARCH ?= $(PROCESSOR_ARCHITECTURE)
 endif
+endif # windows but MINGW_CHOST not defined
 else
 # Normalize some abiguous YQ2_ARCH strings
 YQ2_ARCH ?= $(shell uname -m | sed -e 's/i.86/i386/' -e 's/amd64/x86_64/' -e 's/^arm.*/arm/')
@@ -196,13 +204,12 @@ endif
 
 # ----------
 
-# If we're building with gcc for i386 let's define -ffloat-store.
-# This helps the old and crappy x87 FPU to produce correct values.
-# Would be nice if Clang had something comparable.
+# Using the default x87 float math on 32bit x86 causes rounding trouble
+# -ffloat-store could work around that, but the better solution is to
+# just enforce SSE - every x86 CPU since Pentium3 supports that
+# and this should even improve the performance on old CPUs
 ifeq ($(YQ2_ARCH), i386)
-ifeq ($(COMPILER), gcc)
-override CFLAGS += -ffloat-store
-endif
+override CFLAGS += -msse -mfpmath=sse
 endif
 
 # Force SSE math on x86_64. All sane compilers should do this
@@ -353,6 +360,7 @@ all: config client server game ref_gl1 ref_gl3 ref_soft ref_vk
 config:
 	@echo "Build configuration"
 	@echo "============================"
+	@echo "YQ2_ARCH = $(YQ2_ARCH) COMPILER = $(COMPILER)"
 	@echo "WITH_CURL = $(WITH_CURL)"
 	@echo "WITH_OPENAL = $(WITH_OPENAL)"
 	@echo "WITH_REFVK = $(WITH_REFVK)"
diff --git a/src/game/savegame/savegame.c b/src/game/savegame/savegame.c
index 3889c93b..30d604e9 100644
--- a/src/game/savegame/savegame.c
+++ b/src/game/savegame/savegame.c
@@ -71,7 +71,7 @@
  * load older savegames. This should be bumped if the files
  * in tables/ are changed, otherwise strange things may happen.
  */
-#define SAVEGAMEVER "YQ2-3"
+#define SAVEGAMEVER "YQ2-4"
 
 #ifndef BUILD_DATE
 #define BUILD_DATE __DATE__
@@ -851,7 +851,35 @@ ReadGame(const char *filename)
 	fread(str_os, sizeof(str_os), 1, f);
 	fread(str_arch, sizeof(str_arch), 1, f);
 
+	// for several released versions (up to incl. 7.45), the official Win32 binaries
+	// accidentally had the YQ2ARCH "AMD64" instead of "i386" set due to a bug in the Makefile
+	// so add this workaround for savegames before version 4 (the version was bumped for this fix)
+	qboolean amd64quirk = false;
+#if defined(_WIN32) && (defined(__i386__) || defined(_M_IX86))
+	amd64quirk = (strcmp(str_arch, "AMD64") == 0);
+#endif
+
 	if (!strcmp(str_ver, SAVEGAMEVER))
+	{
+		save_ver = 4;
+
+		if (strcmp(str_game, GAMEVERSION))
+		{
+			fclose(f);
+			gi.error("Savegame from another game.so.\n");
+		}
+		else if (strcmp(str_os, YQ2OSTYPE))
+		{
+			fclose(f);
+			gi.error("Savegame from another os.\n");
+		}
+		else if (strcmp(str_arch, YQ2ARCH))
+		{
+			fclose(f);
+			gi.error("Savegame from another architecture.\n");
+		}
+	}
+	else if (!strcmp(str_ver, "YQ2-3"))
 	{
 		save_ver = 3;
 
@@ -865,7 +893,7 @@ ReadGame(const char *filename)
 			fclose(f);
 			gi.error("Savegame from another os.\n");
 		}
-		else if (strcmp(str_arch, YQ2ARCH))
+		else if (strcmp(str_arch, YQ2ARCH) && !amd64quirk)
 		{
 			fclose(f);
 			gi.error("Savegame from another architecture.\n");
@@ -885,7 +913,7 @@ ReadGame(const char *filename)
 			fclose(f);
 			gi.error("Savegame from another os.\n");
 		}
-		else if (strcmp(str_arch, YQ2ARCH))
+		else if (strcmp(str_arch, YQ2ARCH) && !amd64quirk)
 		{
 			fclose(f);
 			gi.error("Savegame from another architecture.\n");