diff --git a/benchmark/benchmark.py b/benchmark/benchmark.py
index f817ddc98..eb981979d 100644
--- a/benchmark/benchmark.py
+++ b/benchmark/benchmark.py
@@ -63,6 +63,8 @@ def _mount_mp(
 
     Returns Mountpoint version string.
     """
+    bucket = cfg['s3_bucket']
+    stub_mode = str(cfg["stub_mode"]).lower()
 
     if cfg['mountpoint_binary'] is None:
         mountpoint_args = [
@@ -70,15 +72,23 @@ def _mount_mp(
             "run",
             "--quiet",
             "--release",
-            "--",
+            "--features=mock",
         ]
+
+        if stub_mode == "s3_client":
+            # `mock-mount-s3` requires bucket to be prefixed with `sthree-` to verify we're not actually reaching S3
+            logging.debug("using mock-mount-s3 due to `stub_mode`, bucket will be prefixed with \"sthree-\"")
+            bucket = f"sthree-{cfg['s3_bucket']}"
+
+            mountpoint_args.append("--bin=mock-mount-s3")
+
+        # End Cargo command, begin passing arguments to Mountpoint
+        mountpoint_args.append("--")
     else:
         mountpoint_args = [cfg['mountpoint_binary']]
 
     os.makedirs(MP_LOGS_DIRECTORY, exist_ok=True)
 
-    bucket = cfg['s3_bucket']
-
     mountpoint_version_output = subprocess.check_output([*mountpoint_args, "--version"]).decode("utf-8")
     log.info("Mountpoint version: %s", mountpoint_version_output.strip())
 
@@ -118,6 +128,10 @@ def _mount_mp(
     for network_interface in cfg['network']['interface_names']:
         subprocess_args.append(f"--bind={network_interface}")
     if (max_throughput := cfg['network']['maximum_throughput_gbps']) is not None:
+        if stub_mode == "s3_client":
+            raise ValueError(
+                "should not use `stub_mode=s3_client` with `maximum_throughput_gbps`, throughput will be limited"
+            )
         subprocess_args.append(f"--maximum-throughput-gbps={max_throughput}")
 
     if cfg['mountpoint_max_background'] is not None:
@@ -126,7 +140,6 @@ def _mount_mp(
     if cfg['mountpoint_congestion_threshold'] is not None:
         subprocess_env["UNSTABLE_MOUNTPOINT_CONGESTION_THRESHOLD"] = str(cfg["mountpoint_congestion_threshold"])
 
-    stub_mode = str(cfg["stub_mode"]).lower()
     if stub_mode != "off" and cfg["mountpoint_binary"] is not None:
         raise ValueError("Cannot use `stub_mode` with `mountpoint_binary`, `stub_mode` requires recompilation")
     match stub_mode:
@@ -134,6 +147,9 @@ def _mount_mp(
             pass
         case "fs_handler":
             subprocess_env["MOUNTPOINT_BUILD_STUB_FS_HANDLER"] = "1"
+        case "s3_client":
+            # Already handled when building cargo command
+            pass
         case _:
             raise ValueError(f"Unknown stub_mode: {stub_mode}")
 
diff --git a/benchmark/conf/config.yaml b/benchmark/conf/config.yaml
index 138a63b58..c5a62e2f0 100644
--- a/benchmark/conf/config.yaml
+++ b/benchmark/conf/config.yaml
@@ -37,7 +37,7 @@ mountpoint_congestion_threshold: !!null
 with_bwm: false
 
 # Works automatically ONLY where this script manages compilation. It has no effect if `mountpoint_binary` is set.
-stub_mode: "off" # fs_handler
+stub_mode: "off" # fs_handler, s3_client
 
 iterations: 1
 
diff --git a/mountpoint-s3-client/src/mock_client/throughput_client.rs b/mountpoint-s3-client/src/mock_client/throughput_client.rs
index 5ca92e5be..0b2a249dd 100644
--- a/mountpoint-s3-client/src/mock_client/throughput_client.rs
+++ b/mountpoint-s3-client/src/mock_client/throughput_client.rs
@@ -30,8 +30,10 @@ use super::MockBackpressureHandle;
 /// TODO: make it bi-directional, so that upload throughput can be simulated as well.
 pub struct ThroughputMockClient {
     inner: MockClient,
-    /// A throughput rate limiter with one token per byte
-    rate_limiter: LeakyBucket,
+    /// A throughput rate limiter with one token per byte.
+    ///
+    /// If [None], there will be no limit on throughput.
+    rate_limiter: Option<LeakyBucket>,
 }
 
 impl ThroughputMockClient {
@@ -46,7 +48,8 @@ impl ThroughputMockClient {
             .refill_amount(bytes_per_interval as u32)
             .max(config.part_size as u32)
             .tokens(0)
-            .build();
+            .build()
+            .into();
         tracing::info!(?rate_limiter, "new client");
 
         Self {
@@ -55,6 +58,16 @@ impl ThroughputMockClient {
         }
     }
 
+    /// Create a new [ThroughputMockClient] with the given configuration and no throughput limits.
+    ///
+    /// This is effectively the same as a [MockClient], but allows you to use the [ThroughputMockClient] type.
+    pub fn new_unlimited_throughput(config: MockClientConfig) -> Self {
+        Self {
+            inner: MockClient::new(config),
+            rate_limiter: None,
+        }
+    }
+
     /// Add an object to this mock client's bucket
     pub fn add_object(&self, key: &str, value: MockObject) {
         self.inner.add_object(key, value);
@@ -65,7 +78,7 @@ impl ThroughputMockClient {
 pub struct ThroughputGetObjectResponse {
     #[pin]
     request: MockGetObjectResponse,
-    rate_limiter: LeakyBucket,
+    rate_limiter: Option<LeakyBucket>,
 }
 
 #[cfg_attr(not(docsrs), async_trait)]
@@ -94,8 +107,10 @@ impl Stream for ThroughputGetObjectResponse {
         this.request.poll_next(cx).map(|next| {
             next.map(|item| {
                 item.inspect(|body_part| {
-                    // Acquire enough tokens for the number of bytes we want to deliver
-                    block_on(this.rate_limiter.acquire(body_part.data.len() as u32));
+                    if let Some(rate_limiter) = this.rate_limiter {
+                        // Acquire enough tokens for the number of bytes we want to deliver
+                        block_on(rate_limiter.acquire(body_part.data.len() as u32));
+                    }
                 })
             })
         })
diff --git a/mountpoint-s3/src/bin/mock-mount-s3.rs b/mountpoint-s3/src/bin/mock-mount-s3.rs
index 42ef6dc64..1d61f4532 100644
--- a/mountpoint-s3/src/bin/mock-mount-s3.rs
+++ b/mountpoint-s3/src/bin/mock-mount-s3.rs
@@ -1,8 +1,7 @@
 //! A version of `mount-s3` that targets an in-memory mock S3 backend rather than the real service.
 //!
-//! The mock S3 backend supports simulating a target network throughput. The
-//! --maximum-throughput-gbps command-line argument can be used to set the target throughput, which
-//! defaults to 10Gbps.
+//! The mock S3 backend supports simulating a target network throughput.
+//! The `--maximum-throughput-gbps` command-line argument can be used to optionally limit download throughput.
 //!
 //! As a safety measure, this binary works only if the bucket name begins with "sthree-". This makes
 //! sure we can't accidentally confuse this binary with a real `mount-s3` in any of our testing or
@@ -12,7 +11,6 @@
 
 use std::sync::Arc;
 
-use anyhow::anyhow;
 use clap::Parser;
 use futures::executor::ThreadPool;
 
@@ -45,21 +43,28 @@ fn create_mock_client(args: &CliArgs) -> anyhow::Result<(Arc<ThroughputMockClien
 
     tracing::warn!("using mock client");
 
-    let Some(max_throughput_gbps) = args.maximum_throughput_gbps else {
-        return Err(anyhow!(
-            "must set --maximum-throughput-gbps when using mock-mount-s3 binary"
-        ));
+    // TODO: Actually update the mock client to support different part sizes
+    let part_size = {
+        if args.read_part_size.is_some() || args.write_part_size.is_some() {
+            tracing::warn!("mock client does not support separate part sizes for reading and writing, ignoring");
+        }
+        args.part_size
     };
-    tracing::info!("mock client target network throughput {max_throughput_gbps} Gbps");
 
     let config = MockClientConfig {
         bucket: bucket_name,
-        part_size: args.part_size as usize,
+        part_size: part_size as usize,
         unordered_list_seed: None,
         enable_backpressure: true,
         initial_read_window_size: 1024 * 1024 + 128 * 1024, // matching real MP
     };
-    let client = ThroughputMockClient::new(config, max_throughput_gbps as f64);
+
+    let client = if let Some(max_throughput_gbps) = args.maximum_throughput_gbps {
+        tracing::info!("mock client limited to {max_throughput_gbps} Gb/s download throughput");
+        ThroughputMockClient::new(config, max_throughput_gbps as f64)
+    } else {
+        ThroughputMockClient::new_unlimited_throughput(config)
+    };
 
     let runtime = Runtime::new(ThreadPool::builder().name_prefix("runtime").create()?);
 
@@ -85,6 +90,13 @@ fn create_mock_client(args: &CliArgs) -> anyhow::Result<(Arc<ThroughputMockClien
         };
         client.add_object(&key, MockObject::ramp(0x11, size as usize, ETag::for_tests()));
     }
+    // Some objects that are useful for benchmarking
+    for job_num in 0..1024 {
+        let size_gib = 100;
+        let size_bytes = size_gib * 1024u64.pow(3);
+        let key = format!("j{job_num}_{size_gib}GiB.bin");
+        client.add_object(&key, MockObject::constant(1u8, size_bytes as usize, ETag::for_tests()));
+    }
     client.add_object("hello.txt", MockObject::from_bytes(b"hello world", ETag::for_tests()));
     client.add_object("empty", MockObject::from_bytes(b"", ETag::for_tests()));
     client.add_object(