diff --git a/repos/base-hw/src/include/hw/spec/x86_64/register_macros.h b/repos/base-hw/src/include/hw/spec/x86_64/register_macros.h
index ba93e85be7..3720bb8f49 100644
--- a/repos/base-hw/src/include/hw/spec/x86_64/register_macros.h
+++ b/repos/base-hw/src/include/hw/spec/x86_64/register_macros.h
@@ -51,7 +51,7 @@
 	};
 
 #define X86_64_CPUID_REGISTER(name, id, reg, ...) \
-	struct name : Genode::Register<64> \
+	struct name : Genode::Register<32> \
 	{ \
 		static access_t read() \
 		{ \