diff --git a/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/grpcconnector.rs b/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/grpcconnector.rs
index 79c2401..57c35ce 100644
--- a/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/grpcconnector.rs
+++ b/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/grpcconnector.rs
@@ -11,7 +11,7 @@ use tokio_rustls::{rustls::ClientConfig};
 use tonic::{Request};
 
 use threadpool::ThreadPool;
-use std::sync::mpsc::channel;
+use std::sync::mpsc::{channel, sync_channel};
 
 use crate::PubCertificate;
 use crate::grpc_client::compact_tx_streamer_client::CompactTxStreamerClient;
@@ -113,7 +113,7 @@ where F : Fn(&[u8], u64) {
 
     let request = Request::new(BlockRange { start: Some(bs), end: Some(be) });
 
-    let (tx, rx) = channel::<Option<CompactBlock>>();
+    let (tx, rx) = sync_channel::<Option<CompactBlock>>(2048);
     let (ftx, frx) = channel();
 
     pool.execute(move || {
diff --git a/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightclient.rs b/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightclient.rs
index 755f342..424faa5 100644
--- a/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightclient.rs
+++ b/third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightclient.rs
@@ -1660,8 +1660,9 @@ pub fn start_mempool_monitor(lc: Arc<LightClient>) -> Result<(), String> {
         // get_block_range streams an ENTIRE range over ONE gRPC connection, so the batch size is
         // the dominant factor in how many TCP connections a sync opens. The old 1000 meant ~1300
         // connections for a full sync, which on Windows exhausted socket buffers (WSAENOBUFS / os
-        // error 10055). A large batch (25k) cuts that ~50x (~52 connections for a full sync) with
-        // no extra memory — blocks are still streamed + scanned incrementally, not buffered.
+        // error 10055). A large batch (25k) cuts that ~50x (~52 connections for a full sync). Blocks
+        // are now buffered up to 2048 deep (bounded backpressure, C240), still one connection per
+        // 25k batch; scan_batch_size must NOT shrink or Windows WSAENOBUFS returns.
         let scan_batch_size = 25000;
         let mut end_height = std::cmp::min(last_scanned_height + scan_batch_size, latest_block);