diff --git a/cmake/external/openblas.cmake b/cmake/external/openblas.cmake
index 46a2dca4426d6a7d8a468a472f27ebbcb9bc1f1a..2341e3785bd8e951e10e3f6bbf8a32f63e4ae44d 100644
--- a/cmake/external/openblas.cmake
+++ b/cmake/external/openblas.cmake
@@ -40,7 +40,7 @@ IF(NOT ${CBLAS_FOUND})
     ELSE()
         SET(OPENBLAS_COMMIT "v0.2.19")
         SET(OPTIONAL_ARGS "")
-        IF(CMAKE_SYSTEM_PROCESSOR MATCHES "^x86(-64)?$")
+        IF(CMAKE_SYSTEM_PROCESSOR MATCHES "^x86(_64)?$")
             SET(OPTIONAL_ARGS DYNAMIC_ARCH=1 NUM_THREADS=64)
         ENDIF()
     ENDIF()