diff --git a/labscript_devices/PrawnBlaster/blacs_workers.py b/labscript_devices/PrawnBlaster/blacs_workers.py
index 08e5b47d..52733627 100644
--- a/labscript_devices/PrawnBlaster/blacs_workers.py
+++ b/labscript_devices/PrawnBlaster/blacs_workers.py
@@ -13,6 +13,7 @@
 import time
 import labscript_utils.h5_lock
 import h5py
+import numpy as np
 from blacs.tab_base_classes import Worker
 from labscript_utils.connections import _ensure_str
 import labscript_utils.properties as properties
@@ -38,6 +39,7 @@ def init(self):
         global time; import time
         global re; import re
         global numpy; import numpy
+        global struct; import struct
         global zprocess; import zprocess
         self.smart_cache = {}
         self.cached_pll_params = {}
@@ -69,6 +71,27 @@ def init(self):
             self.prawnblaster.write(b"setinpin %d %d\r\n" % (i, in_pin))
             assert self.prawnblaster.readline().decode() == "ok\r\n"
 
+        # Check if fast serial is available
+        version, _ = self.get_version()
+        self.fast_serial = version >= (1, 1, 0)
+
+    def get_version(self):
+        self.prawnblaster.write(b"version\r\n")
+        version_str = self.prawnblaster.readline().decode()
+        assert version_str.startswith("version: ")
+        version = version_str[9:].strip()
+
+        version_overclock_list = version.split('-')
+        overclock = False
+        if len(version_overclock_list) == 2:
+            if version_overclock_list[1] == 'overclock':
+                overclock = True
+
+        version = tuple(int(v) for v in version_overclock_list[0].split('.'))
+        assert len(version) == 3
+
+        return version, overclock
+
     def check_status(self):
         """Checks the operational status of the PrawnBlaster.
 
@@ -292,27 +315,66 @@ def transition_to_buffered(self, device_name, h5file, initial_values, fresh):
 
         # Program instructions
         for pseudoclock, pulse_program in enumerate(pulse_programs):
-            for i, instruction in enumerate(pulse_program):
-                if i == len(self.smart_cache[pseudoclock]):
-                    # Pad the smart cache out to be as long as the program:
-                    self.smart_cache[pseudoclock].append(None)
-
-                # Only program instructions that differ from what's in the smart cache:
-                if self.smart_cache[pseudoclock][i] != instruction:
-                    self.prawnblaster.write(
-                        b"set %d %d %d %d\r\n"
-                        % (
-                            pseudoclock,
-                            i,
-                            instruction["half_period"],
-                            instruction["reps"],
+            total_inst = len(pulse_program)
+            # check if it is more efficient to fully refresh
+            if not fresh and self.smart_cache[pseudoclock] is not None and self.fast_serial:
+                # get more convenient handles to smart cache arrays
+                curr_inst = self.smart_cache[pseudoclock]
+
+                # if arrays aren't of same shape, only compare up to smaller array size
+                n_curr = len(curr_inst)
+                n_new = len(pulse_program)
+                if n_curr > n_new:
+                    # technically don't need to reprogram current elements beyond end of new elements
+                    new_inst = np.sum(curr_inst[:n_new] != pulse_program)
+                elif n_curr < n_new:
+                    n_diff = n_new - n_curr
+                    val_diffs = np.sum(curr_inst != pulse_program[:n_curr])
+                    new_inst = val_diffs + n_diff
+                else:
+                    new_inst = np.sum(curr_inst != pulse_program)
+
+                if new_inst / total_inst > 0.1:
+                    fresh = True
+
+            if (fresh or self.smart_cache[pseudoclock] is None) and self.fast_serial:
+                print('binary programming')
+                self.prawnblaster.write(b"setb %d %d %d\r\n" % (pseudoclock, 0, len(pulse_program)))
+                response = self.prawnblaster.readline().decode()
+                assert (
+                    response == "ready\r\n"
+                ), f"PrawnBlaster said '{response}', expected 'ready'"
+                program_array = np.array([pulse_program['half_period'],
+                                          pulse_program['reps']], dtype='<u4').T
+                self.prawnblaster.write(program_array.tobytes())
+                response = self.prawnblaster.readline().decode()
+                assert (
+                    response == "ok\r\n"
+                ), f"PrawnBlaster said '{response}', expected 'ok'"
+                self.smart_cache[pseudoclock] = pulse_program
+            else:
+                print('incremental programming')
+                for i, instruction in enumerate(pulse_program):
+                    if i == len(self.smart_cache[pseudoclock]):
+                        # Pad the smart cache out to be as long as the program:
+                        self.smart_cache[pseudoclock].append(None)
+
+                    # Only program instructions that differ from what's in the smart cache:
+                    if self.smart_cache[pseudoclock][i] != instruction:
+                        self.prawnblaster.write(
+                            b"set %d %d %d %d\r\n"
+                            % (
+                                pseudoclock,
+                                i,
+                                instruction["half_period"],
+                                instruction["reps"],
+                            )
                         )
-                    )
-                    response = self.prawnblaster.readline().decode()
-                    assert (
-                        response == "ok\r\n"
-                    ), f"PrawnBlaster said '{response}', expected 'ok'"
-                    self.smart_cache[pseudoclock][i] = instruction
+                        response = self.prawnblaster.readline().decode()
+                        assert (
+                            response == "ok\r\n"
+                        ), f"PrawnBlaster said '{response}', expected 'ok'"
+                        self.smart_cache[pseudoclock][i] = instruction
 
         if not self.is_master_pseudoclock:
             # Start the Prawnblaster and have it wait for a hardware trigger