diff --git a/Cargo.lock b/Cargo.lock
index 9516fd50..f3c7b020 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -278,6 +278,20 @@ version = "0.8.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
 
+[[package]]
+name = "dashmap"
+version = "5.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
+dependencies = [
+ "cfg-if",
+ "hashbrown 0.14.5",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core 0.9.10",
+ "rayon",
+]
+
 [[package]]
 name = "dirs"
 version = "5.0.1"
@@ -374,6 +388,12 @@ version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9fc0510504f03c51ada170672ac806f1f105a88aa97a5281117e1ddc3368e51a"
 
+[[package]]
+name = "finl_unicode"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fcfdc7a0362c9f4444381a9e697c79d435fe65b52a37466fc2c1184cee9edc6"
+
 [[package]]
 name = "fixedbitset"
 version = "0.4.2"
@@ -511,10 +531,12 @@ dependencies = [
  "chrono",
  "clap",
  "content_inspector",
+ "dashmap",
  "dirs",
  "dotenv",
  "duct",
  "env_logger",
+ "finl_unicode",
  "graphql_client",
  "hipcheck-macros",
  "indexmap 2.2.6",
@@ -545,7 +567,6 @@ dependencies = [
  "termcolor",
  "toml",
  "unicode-normalization",
- "unicode-segmentation",
  "ureq",
  "url",
  "walkdir",
@@ -796,7 +817,7 @@ checksum = "7d17b78036a60663b797adeaee46f5c9dfebb86948d1255007a1d6be0271ff99"
 dependencies = [
  "instant",
  "lock_api",
- "parking_lot_core",
+ "parking_lot_core 0.8.6",
 ]
 
 [[package]]
@@ -808,11 +829,24 @@ dependencies = [
  "cfg-if",
  "instant",
  "libc",
- "redox_syscall",
+ "redox_syscall 0.2.16",
  "smallvec",
  "winapi",
 ]
 
+[[package]]
+name = "parking_lot_core"
+version = "0.9.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e401f977ab385c9e4e3ab30627d6f26d00e2c73eef317493c4ec6d468726cf8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall 0.5.2",
+ "smallvec",
+ "windows-targets 0.52.5",
+]
+
 [[package]]
 name = "paste"
 version = "1.0.15"
@@ -952,6 +986,15 @@ dependencies = [
  "bitflags 1.3.2",
 ]
 
+[[package]]
+name = "redox_syscall"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c82cf8cff14456045f55ec4241383baeff27af886adb72ffb2162f99911de0fd"
+dependencies = [
+ "bitflags 2.5.0",
+]
+
 [[package]]
 name = "redox_users"
 version = "0.4.5"
diff --git a/hipcheck/Cargo.toml b/hipcheck/Cargo.toml
index 9cd654bd..1dcdfa12 100644
--- a/hipcheck/Cargo.toml
+++ b/hipcheck/Cargo.toml
@@ -54,7 +54,6 @@ spdx-rs = "0.5.0"
 termcolor = "1.1.3"
 toml = "0.8.14"
 unicode-normalization = "0.1.19"
-unicode-segmentation = "1.9.0"
 ureq = { version = "2.9.7", default-features = false, features = [
     "json",
     "tls",
@@ -66,6 +65,8 @@ xml-rs = "0.8.20"
 tempdir = "0.3.7"
 rayon = "1.10.0"
 indexmap = "2.2.6"
+dashmap = { version = "5.5.3", features = ["rayon", "inline"] }
+finl_unicode = { version = "1.2.0", default-features = false, features = ["grapheme_clusters"] }
 
 # Windows-specific dependencies
 [target.'cfg(windows)'.dependencies]
diff --git a/hipcheck/src/cli.rs b/hipcheck/src/cli.rs
index e7ebd02d..9fbd938f 100644
--- a/hipcheck/src/cli.rs
+++ b/hipcheck/src/cli.rs
@@ -396,9 +396,6 @@ pub enum Commands {
 	Unstable(UnstableArgs),
 }
 
-// If no subcommand matched, default to use of '-t <TYPE> <TARGET' syntax. In
-// this case, `target` is a required field, but the existence of a subcommand
-// removes that requirement
 #[derive(Debug, Clone, clap::Args)]
 pub struct UnstableArgs {
 	#[clap(subcommand)]
diff --git a/hipcheck/src/metric/entropy.rs b/hipcheck/src/metric/entropy.rs
index 00ef1f8c..e303f6e8 100644
--- a/hipcheck/src/metric/entropy.rs
+++ b/hipcheck/src/metric/entropy.rs
@@ -3,7 +3,6 @@
 use crate::context::Context as _;
 use crate::data::git::Commit;
 use crate::data::git::CommitDiff;
-use crate::data::git::Diff;
 use crate::error::Result;
 use crate::hc_error;
 use crate::metric::math::mean;
@@ -12,13 +11,15 @@ use crate::metric::MetricProvider;
 use crate::TryAny;
 use crate::TryFilter;
 use crate::F64;
+use dashmap::DashMap;
+use finl_unicode::grapheme_clusters::Graphemes;
+use rayon::prelude::*;
 use serde::Serialize;
 use std::collections::HashMap;
 use std::iter::Iterator;
 use std::ops::Not as _;
 use std::sync::Arc;
 use unicode_normalization::UnicodeNormalization;
-use unicode_segmentation::UnicodeSegmentation;
 
 /// Analyze a source to produce a set of entropy scores for its commits.
 ///
@@ -150,8 +151,68 @@ fn is_likely_source_file(
 
 /// Calculate grapheme frequencies for each commit.
 fn grapheme_freqs(commit_diff: &CommitDiff, db: &dyn MetricProvider) -> Result<CommitGraphemeFreq> {
-	let grapheme_freqs = GraphemeFreqCalculator::for_diff(&commit_diff.diff, db)?.calculate();
+	// Dashmap (fast concurrent hashmap) to store counts for each grapheme.
+	let grapheme_table: DashMap<String, u64> = DashMap::new();
+
+	// Use this variable to track the total number of graphemes accross all patches in this commit diff.
+	let mut total_graphemes: usize = 0;
+
+	// Iterate over the file diffs by reference.
+	for file_diff in &commit_diff.diff.file_diffs {
+		// Filter out any that are probably not source files.
+		if db
+			.is_likely_source_file(Arc::clone(&file_diff.file_name))?
+			.not()
+		{
+			continue;
+		}
+
+		// Filter out any that are empty.
+		if file_diff.patch.is_empty() {
+			continue;
+		}
+
+		// Count the number of graphemes in this patch, add it to the tortal,
+		// and track the number of each grapheme.
+		total_graphemes += file_diff
+			.patch
+			// Iterate in parallel over the lines of the patch.
+			.par_lines()
+			// Normalize each line.
+			// See https://en.wikipedia.org/wiki/Unicode_equivalence.
+			.map(|line: &str| line.chars().nfc().collect::<String>())
+			// Count the graphemes in each normalized line.
+			// Also update the graphemes table here.
+			// We'll sum these counts to get the total number of graphemes.
+			.map(|normalized_line: String| {
+				// Create an iterator over the graphemes in the line.
+				Graphemes::new(&normalized_line)
+					// Update the graphemes table.
+					.map(|grapheme: &str| {
+						// Use this if statement to avoid allocating a new string unless needed.
+						if let Some(mut count) = grapheme_table.get_mut(grapheme) {
+							*count += 1;
+						} else {
+							grapheme_table.insert(grapheme.to_owned(), 1);
+						}
+					})
+					// get the grapheme count for this normalized line.
+					.count()
+			})
+			.sum::<usize>();
+	}
 
+	// Transform out table (dashmap) of graphemes and their frequencies into a list to return.
+	let grapheme_freqs = grapheme_table
+		// Iterate in parallel for performance.
+		.into_par_iter()
+		.map(|(grapheme, count)| GraphemeFreq {
+			grapheme,
+			freq: count as f64 / total_graphemes as f64,
+		})
+		.collect();
+
+	// Return the collected list of graphemes and their frequencies for this commit diff.
 	Ok(CommitGraphemeFreq {
 		commit: Arc::clone(&commit_diff.commit),
 		grapheme_freqs,
@@ -228,61 +289,3 @@ fn z_scores(mut commit_entropies: Vec<CommitEntropy>) -> Result<Vec<CommitEntrop
 
 	Ok(commit_entropies)
 }
-
-/// A helper struct for calculating frequencies of individual graphemes.
-#[derive(Debug, Default)]
-struct GraphemeFreqCalculator {
-	/// The count of each grapheme in the diff.
-	grapheme_counts: HashMap<String, u64>,
-	/// The total number of graphemes in the diff.
-	grapheme_total: u64,
-}
-
-impl GraphemeFreqCalculator {
-	/// Initialize the calculator with data from a specific diff, filtering out
-	/// non-source-file changes.
-	fn for_diff(diff: &Diff, db: &dyn MetricProvider) -> Result<GraphemeFreqCalculator> {
-		let mut cgf = GraphemeFreqCalculator::default();
-
-		for file_diff in &diff.file_diffs {
-			if db.is_likely_source_file(Arc::clone(&file_diff.file_name))?
-				&& file_diff.patch.is_empty().not()
-			{
-				for line in file_diff.patch.lines() {
-					cgf.add_line(line);
-				}
-			}
-		}
-
-		Ok(cgf)
-	}
-
-	/// Used by the constructor to add individual diff line data to the calculator.
-	#[allow(clippy::suspicious_map)]
-	fn add_line(&mut self, line: &str) {
-		let line = line.chars().nfc().collect::<String>();
-
-		self.grapheme_total += line
-			.graphemes(true)
-			.map(|grapheme| {
-				let grapheme = grapheme.to_owned();
-				let entry = self.grapheme_counts.entry(grapheme).or_insert(0);
-				*entry += 1;
-			})
-			.count() as u64;
-	}
-
-	/// Calculate the grapheme frequencies based on the data collected in the calculator.
-	fn calculate(self) -> Vec<GraphemeFreq> {
-		let mut grapheme_freqs = Vec::new();
-
-		for (grapheme, count) in self.grapheme_counts {
-			grapheme_freqs.push(GraphemeFreq {
-				grapheme,
-				freq: count as f64 / self.grapheme_total as f64,
-			});
-		}
-
-		grapheme_freqs
-	}
-}