diff --git a/unicode-data-scripts/bench/Main.hs b/unicode-data-scripts/bench/Main.hs
index 721d01a..cd06dee 100644
--- a/unicode-data-scripts/bench/Main.hs
+++ b/unicode-data-scripts/bench/Main.hs
@@ -1,55 +1,249 @@
-import Control.DeepSeq (NFData, deepseq, force)
-import Control.Exception (evaluate)
-import Data.Ix (Ix(..))
-import Test.Tasty.Bench
-    (Benchmark, bgroup, bench, defaultMain, env, nf)
+{-# LANGUAGE CPP #-}
+
+import Control.DeepSeq (NFData (..), deepseq)
+import Control.Exception (assert, evaluate)
+import Data.Char (ord)
+import Data.Ix (Ix (..))
+import Foreign (Storable (..))
+import qualified GHC.Exts as Exts
+import GHC.IO (IO (..))
+import Test.Tasty.Bench (
+    Benchmark,
+    bench,
+    bgroup,
+    defaultMain,
+    nf, env, bcompare,
+ )
 
 #if MIN_VERSION_base(4,10,0) && !MIN_VERSION_base(4,15,0)
 import qualified GHC.Magic as Exts (noinline)
 #endif
 
-import qualified Unicode.Char.General as G
+#ifdef HAS_ICU
+import qualified ICU.Scripts as ICU
+#endif
+
 import qualified Unicode.Char.General.Scripts as S
 
 main :: IO ()
 main = defaultMain
-  [ bgroup "Unicode.Char.General.Script"
-    [ bgroup "script"
-      [ benchChars "unicode-data"  (show . S.script)
+  [ bgroupWithCharRange "Unicode.Char.General.Script" charRange $ \chars ->
+    [ bgroupWithChars "script" chars
+      [ Bench "unicode-data" (fromEnum . S.script)
+#ifdef HAS_ICU
+      , Bench "icu" (fromEnum . ICU.codepointScript . fromIntegral . ord)
+#endif
       ]
     , bgroup "scriptDefinition"
-      [ benchNF "unicode-data"  (show . S.scriptDefinition)
+      [ benchNF "unicode-data" S.scriptDefinition
       ]
-    , bgroup "scriptExtensions"
-      [ benchChars "unicode-data"  (show . S.scriptExtensions)
+    , bgroupWithChars "scriptExtensions" chars
+      [ Bench "unicode-data" (fmap fromEnum . S.scriptExtensions)
+#ifdef HAS_ICU
+      , Bench "icu" (fmap fromEnum . ICU.scriptExtensions)
+#endif
       ]
     ]
   ]
   where
-    benchChars :: forall a. (NFData a) => String -> (Char -> a) -> Benchmark
-    benchChars t f =
-        -- Avoid side-effects with garbage collection (see tasty-bench doc)
-        env
-            (evaluate (force chars)) -- initialize
-            (bench t . nf (foldString f)) -- benchmark
+  charRange = CharRange minBound maxBound
+
+benchNF
+    :: forall a b. (Bounded a, Ix a, NFData b)
+    => String
+    -> (a -> b)
+    -> Benchmark
+benchNF t f = bench t (nf (fold_ f) (minBound, maxBound))
+
+fold_
+    :: forall a b. (Ix a, NFData b)
+    => (a -> b)
+    -> (a, a)
+    -> ()
+fold_ f = foldr (deepseq . f) () . range
+
+--------------------------------------------------------------------------------
+-- Characters benchmark
+--------------------------------------------------------------------------------
+
+-- | A unit benchmark
+data Bench a = Bench
+  { _title :: !String     -- ^ Name
+  , _func :: !(Char -> a) -- ^ Function to benchmark
+  }
+
+-- | Helper to compare benchmarks of function from this package to ones in base.
+{-# INLINE bgroupWithValidCharRange #-}
+bgroupWithValidCharRange ::
+    String ->
+    CharRange ->
+    (Char -> Bool) ->
+    (Chars -> [Benchmark]) ->
+    Benchmark
+bgroupWithValidCharRange groupTitle charRange isValid mkBenches =
+    -- Avoid side-effects with garbage collection (see tasty-bench doc for env).
+    -- We use pinned ByteArray# instead of lists to avoid that GC kicks in.
+    env
+        (initialize isValid charRange >>= evaluate)
+        (bgroup groupTitle . mkBenches)
+
+-- | Helper to compare benchmarks of function from this package to ones in base.
+-- Filter out Surrogates, Private Use Areas and unsassigned code points.
+{-# INLINE bgroupWithCharRange #-}
+bgroupWithCharRange ::
+    String ->
+    CharRange ->
+    (Chars -> [Benchmark]) ->
+    Benchmark
+bgroupWithCharRange title charRange =
+    bgroupWithValidCharRange title charRange isValid
+    where
+    isValid c = S.script c /= S.Unknown
+
+{-# INLINE benchCharsRange #-}
+benchCharsRange :: NFData a => String -> String -> Chars -> (Char -> a) -> Benchmark
+benchCharsRange groupTitle title chars = case title of
+    "icu" -> benchCharsNF title chars
+    _     -> bcompare' "icu" . benchCharsNF title chars
+    where
+    {-# INLINE bcompare' #-}
+    -- [NOTE] Works if groupTitle uniquely identifies the benchmark group.
+    bcompare' ref = bcompare
+        (mconcat ["$NF == \"", ref, "\" && $(NF-1) == \"", groupTitle, "\""])
+
+-- | Helper to compare benchmarks of function from this package to ones in base.
+{-# INLINE bgroupWithChars #-}
+bgroupWithChars :: (NFData a) => String -> Chars -> [Bench a] -> Benchmark
+bgroupWithChars groupTitle chars bs = bgroup groupTitle
+    [ benchCharsRange groupTitle title chars f
+    | Bench title f <- bs
+    ]
+
+-- | Helper to bench a char function on a filtered char range
+{-# INLINE benchCharsNF #-}
+benchCharsNF
+    :: (NFData a)
+    => String
+    -> Chars
+    -> (Char -> a)
+    -> Benchmark
+benchCharsNF title chars f = bench title (nf (foldrChars f) chars)
+
+--------------------------------------------------------------------------------
+-- Chars byte array
+--------------------------------------------------------------------------------
+
+-- | Characters range
+data CharRange = CharRange !Char !Char
+
+-- | Pinned array of characters
+data Chars = Chars !Exts.ByteArray# !Int
+
+instance NFData Chars where
+    rnf (Chars !_ !_) = ()
+
+-- | Fold over a chars byte array
+foldrChars :: NFData a => (Char -> a) -> Chars -> ()
+foldrChars f = go
+    where
+    -- Loop over the pinned char array. The loop itself does not allocate.
+    go (Chars cs len) = foldr
+        (\(Exts.I# k) ->
+            let c = Exts.indexWideCharArray# cs (k Exts.-# 1#)
+#if MIN_VERSION_base(4,10,0)
+            -- `inline` is necessary to avoid excessive inlining, resulting
+            -- in benchmarking empty loop iterations, i.e. not the function.
+            -- We could use `inline` with more care at call site, but then we
+            -- would have to test the functions one by one and everytime we
+            -- modify them. Using it here is a hammer but more secure and
+            -- maintainable.
+            -- Note that we may improve this by controling the inlining for each
+            -- phase.
+            in deepseq (Exts.noinline f (Exts.C# c)))
+#else
+            -- HACK: No `inline` for GHC < 8.2. Should we drop support?
+            in deepseq (f (Exts.C# c)))
+#endif
+        ()
+        [1..len]
+
+-- | Create a byte array of the chars to bench
+initialize :: (Char -> Bool) -> CharRange -> IO Chars
+initialize isValid charRange = IO $ \s1 ->
+    case Exts.newPinnedByteArray# initialLength s1 of { (# s2, ma #) ->
+    -- Write the filtered char range
+    case writeChars isValid ma 0# s2 start end of { (# s3, filteredCount #) ->
+    -- Duplicate to get enough chars to bench
+    case tile ma 0# finalLength filteredLength s3 of { s4 ->
+    case Exts.unsafeFreezeByteArray# ma s4 of { (# s5, a #) ->
+        (# s5, Chars a (Exts.I# (replications Exts.*# filteredCount)) #)
+    }}
+       where
+       -- Ensure to have enough chars
+       replications = case Exts.quotInt# targetCharsCount filteredCount of
+           0# -> 1#
+           r# -> r#
+       filteredLength = filteredCount Exts.*# wcharSize
+       finalLength = filteredLength Exts.*# replications
+   }}
+    where
+    targetCharsCount = 0x10FFFF#
+    !(CharRange start end) = assert
+        (ord end - ord start + 1 < Exts.I# targetCharsCount)
+        charRange
+    !initialLength = targetCharsCount Exts.*# wcharSize
+    !(Exts.I# wcharSize) = sizeOf 'x'
+
+-- | Write a range of chars that match the given predicate
+writeChars ::
+    (Char -> Bool) ->
+    Exts.MutableByteArray# d ->
+    Exts.Int# ->
+    Exts.State# d ->
+    Char ->
+    Char ->
+    (# Exts.State# d, Exts.Int# #)
+writeChars isValid ma = go
+    where
+    go i s c1@(Exts.C# c1#) !c2 = if c1 < c2
+        then go i' s' (succ c1) c2
+        else (# s', i' #)
         where
-        -- Filter out: Surrogates, Private Use Areas and unsassigned code points
-        chars = filter isValid [minBound..maxBound]
-        isValid c = G.generalCategory c < G.Surrogate
-
-    foldString :: forall a. (NFData a) => (Char -> a) -> String -> ()
-    foldString f = foldr (deepseq . f) ()
-
-    benchNF
-        :: forall a b. (Bounded a, Ix a, NFData b)
-        => String
-        -> (a -> b)
-        -> Benchmark
-    benchNF t f = bench t (nf (fold_ f) (minBound, maxBound))
-
-    fold_
-        :: forall a b. (Ix a, NFData b)
-        => (a -> b)
-        -> (a, a)
-        -> ()
-    fold_ f = foldr (deepseq . f) () . range
+        !(# s', i' #) = if isValid c1
+            then (# Exts.writeWideCharArray# ma i c1# s, i Exts.+# 1# #)
+            else (# s, i #)
+
+-- | Duplicate a portion of an array
+--
+-- Adapted from Data.Text.Array.tile
+tile ::
+    -- | Mutable array
+    Exts.MutableByteArray# s ->
+    -- | Start of the portion to duplicate
+    Exts.Int# ->
+    -- | Total length of the duplicate
+    Exts.Int# ->
+    -- | Length of the portion to duplicate
+    Exts.Int# ->
+    Exts.State# s ->
+    Exts.State# s
+tile dest destOff totalLen = go
+    where
+    go l s
+        | Exts.isTrue# ((2# Exts.*# l) Exts.># totalLen) =
+            Exts.copyMutableByteArray#
+                dest
+                destOff
+                dest
+                (destOff Exts.+# l)
+                (totalLen Exts.-# l)
+                s
+        | otherwise =
+            case Exts.copyMutableByteArray#
+                    dest
+                    destOff
+                    dest
+                    (destOff Exts.+# l)
+                    l
+                    s of
+                        s' -> go (2# Exts.*# l) s'
diff --git a/unicode-data-scripts/unicode-data-scripts.cabal b/unicode-data-scripts/unicode-data-scripts.cabal
index b7c151d..dbd8aab 100644
--- a/unicode-data-scripts/unicode-data-scripts.cabal
+++ b/unicode-data-scripts/unicode-data-scripts.cabal
@@ -131,3 +131,7 @@ benchmark bench
   -- [NOTE] Recommendation of tasty-bench for comparison against baseline
   if impl(ghc >= 8.6)
     ghc-options: -fproc-alignment=64
+  if flag(dev-has-icu)
+    build-depends:
+      icu
+    cpp-options: -DHAS_ICU