diff --git a/CMakeLists.txt b/CMakeLists.txt
index 34013d0..0e37d88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -86,9 +86,9 @@ include(CMakePackageConfigHelpers)
 set (NCI_INTEL_FLAGS "-r8 -i4 -w -fpe0 -ftz -convert big_endian -assume byterecl -check noarg_temp_created")
 set (NCI_REPRO_FLAGS "-fp-model precise -fp-model source -align all")
 if (CICE_DETERMINISTIC)
-  set (NCI_OPTIM_FLAGS "-g0 -O0 -axCORE-AVX2 -debug none -check none -assume buffered_io")
+  set (NCI_OPTIM_FLAGS "-g0 -O0 -debug none -check none -assume buffered_io")
 else ()
-  set (NCI_OPTIM_FLAGS "-g3 -O2 -axCORE-AVX2 -debug all -check none -traceback -assume buffered_io")
+  set (NCI_OPTIM_FLAGS "-g3 -O2 -debug all -check none -traceback -assume buffered_io")
   set (NCI_DEBUG_FLAGS "-g3 -O0 -debug all -check all -no-vec -traceback -assume nobuffered_io")
 endif ()
 
@@ -317,4 +317,4 @@ set_target_properties(cice PROPERTIES
 install(TARGETS cice
   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
   COMPONENT IO_${CICE_IO}
-)
\ No newline at end of file
+)