diff --git a/copyparty/szip.py b/copyparty/szip.py
index e91bdcca..85d5a9cc 100644
--- a/copyparty/szip.py
+++ b/copyparty/szip.py
@@ -276,6 +276,7 @@ class StreamZip(StreamArc):
     def gen(self) -> Generator[bytes, None, None]:
         errf: dict[str, Any] = {}
         errors = []
+        mbuf = b""
         try:
             for f in self.fgen:
                 if "err" in f:
@@ -284,13 +285,20 @@ class StreamZip(StreamArc):
 
                 try:
                     for x in self.ser(f):
-                        yield x
+                        mbuf += x
+                        if len(mbuf) >= 16384:
+                            yield mbuf
+                            mbuf = b""
                 except GeneratorExit:
                     raise
                 except:
                     ex = min_ex(5, True).replace("\n", "\n-- ")
                     errors.append((f["vp"], ex))
 
+            if mbuf:
+                yield mbuf
+                mbuf = b""
+
             if errors:
                 errf, txt = errdesc(errors)
                 self.log("\n".join(([repr(errf)] + txt[1:])))
@@ -300,20 +308,23 @@ class StreamZip(StreamArc):
             cdir_pos = self.pos
             for name, sz, ts, crc, h_pos in self.items:
                 buf = gen_hdr(h_pos, name, sz, ts, self.utf8, crc, self.pre_crc)
-                yield self._ct(buf)
+                mbuf += self._ct(buf)
+                if len(mbuf) >= 16384:
+                    yield mbuf
+                    mbuf = b""
             cdir_end = self.pos
 
             _, need_64 = gen_ecdr(self.items, cdir_pos, cdir_end)
             if need_64:
                 ecdir64_pos = self.pos
                 buf = gen_ecdr64(self.items, cdir_pos, cdir_end)
-                yield self._ct(buf)
+                mbuf += self._ct(buf)
 
                 buf = gen_ecdr64_loc(ecdir64_pos)
-                yield self._ct(buf)
+                mbuf += self._ct(buf)
 
             ecdr, _ = gen_ecdr(self.items, cdir_pos, cdir_end)
-            yield self._ct(ecdr)
+            yield mbuf + self._ct(ecdr)
         finally:
             if errf:
                 bos.unlink(errf["ap"])
diff --git a/copyparty/util.py b/copyparty/util.py
index 2c2666bb..fdb8d096 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -2125,7 +2125,7 @@ def list_ips() -> list[str]:
 def yieldfile(fn: str) -> Generator[bytes, None, None]:
     with open(fsenc(fn), "rb", 512 * 1024) as f:
         while True:
-            buf = f.read(64 * 1024)
+            buf = f.read(128 * 1024)
             if not buf:
                 break