diff --git a/CHANGES.md b/CHANGES.md
index 28e194af..d514c638 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,9 @@
+## [0.2.19.2] – September 2023
+
+    * [By default pass `-msse4.2` on x86 architectures](https://github.com/haskell-unordered-containers/unordered-containers/pull/483)
+
+[0.2.19.2]: https://github.com/haskell-unordered-containers/unordered-containers/compare/v0.2.19.1...v0.2.19.2
+
 ## [0.2.19.1] – April 2022
 
 * [Fix bug in `intersection[With[Key]]`](https://github.com/haskell-unordered-containers/unordered-containers/pull/427)
diff --git a/unordered-containers.cabal b/unordered-containers.cabal
index d16adc73..9ab1c75d 100644
--- a/unordered-containers.cabal
+++ b/unordered-containers.cabal
@@ -42,6 +42,14 @@ flag debug
   description:  Enable debug support
   default:      False
 
+flag sse42
+  description: Instruct GHC to use -msse4.2. Disable this to allow
+               older architectures to use unordered-containers. Only relevant
+               for x86; expect performance regressions on newer architectures
+               when disabled.
+  default:     True
+  manual:      True
+
 library
   exposed-modules:
     Data.HashMap.Internal
@@ -70,6 +78,9 @@ library
     BangPatterns
 
   ghc-options: -Wall -O2 -fwarn-tabs -ferror-spans
+  if flag(sse42) && arch(x86_64)
+    -- only enable flag on x86
+    ghc-options: -msse4.2
 
   -- For dumping the generated code:
   -- ghc-options: -ddump-simpl -ddump-stg-final -ddump-cmm -ddump-asm -ddump-to-file