diff --git a/backend/telemetry_core/src/main.rs b/backend/telemetry_core/src/main.rs
index ccec9a5..e223911 100644
--- a/backend/telemetry_core/src/main.rs
+++ b/backend/telemetry_core/src/main.rs
@@ -59,10 +59,11 @@ struct Opts {
     /// to a feed, the feed connection will be closed.
     #[structopt(long, default_value = "10")]
     feed_timeout: u64,
-    /// Number of worker threads to spawn. Defaults to the number of CPUs on the machine.
-    /// If "0" is given, use the number of CPUs available on the machine.
-    #[structopt(long)]
-    worker_threads: Option<usize>,
+    /// Number of worker threads to spawn. If "0" is given, use the number of CPUs available
+    /// on the machine. Note that the tokio runtime performance seems to degrade when this number
+    /// gets too high.
+    #[structopt(long, default_value = "8")]
+    worker_threads: usize,
 }
 
 fn main() {
@@ -75,9 +76,10 @@ fn main() {
 
     log::info!("Starting Telemetry Core version: {}", VERSION);
 
-    let worker_threads = opts.worker_threads
-        .and_then(|n| if n == 0 { None } else { Some(n) })
-        .unwrap_or_else(|| num_cpus::get());
+    let worker_threads = match opts.worker_threads {
+        0 => num_cpus::get(),
+        n => n
+    };
 
     tokio::runtime::Builder::new_multi_thread()
         .enable_all()
@@ -307,7 +309,7 @@ async fn handle_feed_websocket_connection<S>(
     mut ws_recv: http_utils::WsReceiver,
     mut tx_to_aggregator: S,
     feed_timeout: u64,
-    feed_id: u64
+    _feed_id: u64 // <- can be useful for debugging purposes.
 ) -> (S, http_utils::WsSender)
 where
     S: futures::Sink<FromFeedWebsocket, Error = anyhow::Error> + Unpin + Send + 'static,
@@ -381,7 +383,7 @@ where
         drop(send_closer_tx); // Kill the send task if this recv task ends
         tx_to_aggregator
     });
-let mut i: u64 = 0;
+
     // Send messages to the feed:
     let send_handle = tokio::spawn(async move {
         'outer: loop {
@@ -398,16 +400,11 @@ let mut i: u64 = 0;
                 None => break,
             };
 
-if feed_id == 1 {
-    i += 1;
-    println!("FEED #{}, msgs: {}", i, msgs.len());
-}
-            // End the loop when there are more than 10k messages queued up.
-            // This number is just picked as a fairly high limit that should account
-            // for many thousands of nodes on a chain. The higher this number is, the
-            // larger our channel storage and memory usage is liable to grow before the feed
-            // is dropped.
-            if msgs.len() > 100_000 {
+            // End the loop if we see more than 1k messages queued up to send out.
+            // This is either because the feed is being too slow to receive messages,
+            // or because the telemetry_core is under too much load and this task isn't
+            // getting enough time.
+            if msgs.len() > 1000 {
                 log::warn!("Closing feed websocket that was too slow to keep up (too many messages buffered)");
                 break 'outer;
             }
diff --git a/backend/telemetry_shard/src/main.rs b/backend/telemetry_shard/src/main.rs
index 8158b24..357a83f 100644
--- a/backend/telemetry_shard/src/main.rs
+++ b/backend/telemetry_shard/src/main.rs
@@ -80,10 +80,11 @@ struct Opts {
     /// value prevented from reconnecting to this shard for, in seconds.
     #[structopt(long, default_value = "600")]
     node_block_seconds: u64,
-    /// Number of worker threads to spawn. Defaults to the number of CPUs on the machine.
-    /// If "0" is given, use the number of CPUs available on the machine.
-    #[structopt(long)]
-    worker_threads: Option<usize>,
+    /// Number of worker threads to spawn. If "0" is given, use the number of CPUs available
+    /// on the machine. Note that the tokio runtime performance seems to degrade when this number
+    /// gets too high.
+    #[structopt(long, default_value = "4")]
+    worker_threads: usize,
 }
 
 fn main() {
@@ -96,9 +97,10 @@ fn main() {
 
     log::info!("Starting Telemetry Shard version: {}", VERSION);
 
-    let worker_threads = opts.worker_threads
-        .and_then(|n| if n == 0 { None } else { Some(n) })
-        .unwrap_or_else(|| num_cpus::get());
+    let worker_threads = match opts.worker_threads {
+        0 => num_cpus::get(),
+        n => n
+    };
 
     tokio::runtime::Builder::new_multi_thread()
         .enable_all()