diff --git a/Cargo.lock b/Cargo.lock
index bb54d4d41..a811a4263 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1589,10 +1589,9 @@ dependencies = [
 [[package]]
 name = "csv"
 version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac574ff4d437a7b5ad237ef331c17ccca63c46479e5b5453eb8e10bb99a759fe"
+source = "git+https://github.com/jqnatividad/rust-csv?branch=qsv-optimized#ce2fb0721c32ab512e58ee4d73976b656b4584ad"
 dependencies = [
- "csv-core",
+ "csv-core 0.1.11 (git+https://github.com/jqnatividad/rust-csv?branch=qsv-optimized)",
  "itoa",
  "ryu",
  "serde",
@@ -1607,6 +1606,14 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "csv-core"
+version = "0.1.11"
+source = "git+https://github.com/jqnatividad/rust-csv?branch=qsv-optimized#ce2fb0721c32ab512e58ee4d73976b656b4584ad"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "csv-diff"
 version = "0.1.0"
@@ -5189,7 +5196,7 @@ dependencies = [
  "bitflags 2.6.0",
  "bytecount",
  "csv",
- "csv-core",
+ "csv-core 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashbrown 0.14.5",
  "memchr",
  "qsv-dateparser",
diff --git a/Cargo.toml b/Cargo.toml
index 47d07d524..c14f407ae 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -252,6 +252,9 @@ rusqlite = { version = "0.31", features = ["bundled"] }
 serial_test = { version = "3.1", features = ["file_locks"] }
 
 [patch.crates-io]
+# use our tweaked fork of csv crate
+# the csv crate underpins a lot of qsv's functionality, so every perf tweak helps
+csv = { git = "https://github.com/jqnatividad/rust-csv", branch = "qsv-optimized" }
 # needed as dynfmt doesn't work in release mode without this
 # see https://github.com/jan-auer/dynfmt/pull/9
 dynfmt = { git = "https://github.com/jqnatividad/dynfmt", branch = "2021-clippy_ptr_as_ptr-bumpdeps" }
@@ -263,7 +266,7 @@ calamine = { git = "https://github.com/tafia/calamine", rev = "a90e877" }
 local-encoding = { git = "https://github.com/slonopotamus/local-encoding-rs", branch = "travis-madness" }
 # Polars has a much higher release tempo for its Python bindings compared
 # to its underlying Rust library. See https://github.com/pola-rs/polars/releases
-# It's qsv's policy to use the latest release of py-polars
+# It's qsv's policy to use the latest release of polars/py-polars
 # to take advantage of Polars' latest features and fixes.
 # polars = { git = "https://github.com/pola-rs/polars", tag = "py-1.4.1" }
 polars = { git = "https://github.com/pola-rs/polars", rev = "1dc2533" }