Update per @acmorrow feedback.

Author: Anthony Sansone

source/includes/fact-mmapv1-big-endian.rst

@@ -1,6 +1,6 @@
 .. important::
 
-   :doc:`MMAPv1 </core/mmapv1>` is unsupported on all big-endian
-   architectures like the IBM z/Architecture (``s390x``) and the
-   PowerPC (``ppc64le``) architecture. MongoDB returns an error when starting a :binary:`~bin.mongod` using MMAPv1 on an unsupported architecture.
-
+   :doc:`MMAPv1 </core/mmapv1>` is supported on 64-bit Intel
+   architectures (``x86_64``) only. MongoDB returns an error when
+   starting a :binary:`~bin.mongod` using MMAPv1 on an unsupported
+   architecture.