diff --git a/10-OBD-Display-2024/display_gif_embedded/include/lv_conf.h b/10-OBD-Display-2024/display_gif_embedded/include/lv_conf.h
index 3a63501..4939f5f 100644
--- a/10-OBD-Display-2024/display_gif_embedded/include/lv_conf.h
+++ b/10-OBD-Display-2024/display_gif_embedded/include/lv_conf.h
@@ -201,7 +201,7 @@
  *-----------*/
 
 /*Enable the log module*/
-#define LV_USE_LOG 1
+#define LV_USE_LOG 0
 #if LV_USE_LOG
 
     /*How important log should be added:
diff --git a/10-OBD-Display-2024/display_gif_embedded/include/scr_st77916.h b/10-OBD-Display-2024/display_gif_embedded/include/scr_st77916.h
index 184a4a8..82ac61f 100644
--- a/10-OBD-Display-2024/display_gif_embedded/include/scr_st77916.h
+++ b/10-OBD-Display-2024/display_gif_embedded/include/scr_st77916.h
@@ -10,6 +10,7 @@
 #define SCREEN_RES_VER 360
 
 static lv_color_t *disp_draw_buf;
+static lv_color_t *disp_draw_buf2; // second buffer: LVGL renders into one while the other is sent to the LCD
 static lv_disp_draw_buf_t draw_buf;
 static lv_disp_drv_t disp_drv;
 static lv_indev_t *indev_touchpad;
@@ -418,8 +419,9 @@ void scr_lvgl_init()
   size_t lv_cache_rows = 72;
 
   disp_draw_buf = (lv_color_t *)heap_caps_malloc(lv_cache_rows * SCREEN_RES_HOR * 2, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
+  disp_draw_buf2 = (lv_color_t *)heap_caps_malloc(lv_cache_rows * SCREEN_RES_HOR * 2, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
   lv_init();
-  lv_disp_draw_buf_init(&draw_buf, disp_draw_buf, NULL, SCREEN_RES_HOR * lv_cache_rows);
+  lv_disp_draw_buf_init(&draw_buf, disp_draw_buf, disp_draw_buf2, SCREEN_RES_HOR * lv_cache_rows);
 
   lv_disp_drv_init(&disp_drv);
   disp_drv.hor_res = SCREEN_RES_HOR;
diff --git a/10-OBD-Display-2024/display_gif_embedded/platformio.ini b/10-OBD-Display-2024/display_gif_embedded/platformio.ini
index a306284..1e006f4 100644
--- a/10-OBD-Display-2024/display_gif_embedded/platformio.ini
+++ b/10-OBD-Display-2024/display_gif_embedded/platformio.ini
@@ -1,29 +1,32 @@
-; JC3636W518 — ESP32-S3R8, 16 MB QIO flash, 8 MB OPI PSRAM, 360x360 ST77916 QSPI + CST816S
-; Settings mirror the vendor Arduino IDE setup (2-Program Example/Demo_Arduino/docs/Arduino set up.png)
-
-[env:jc3636w518]
-; pioarduino = Arduino core 3.0.5 (ESP32_Display_Panel 0.1.4 needs core 3.x)
-platform = https://github.com/pioarduino/platform-espressif32/releases/download/51.03.05/platform-espressif32.zip
-board = esp32-s3-devkitc-1
-framework = arduino
-
-board_build.arduino.memory_type = qio_opi
-board_build.flash_mode = qio
-board_upload.flash_size = 16MB
-; GIF compiled into firmware -> 3.4 MB, too big for huge_app (3 MB); 6.25 MB app slots
-board_build.partitions = default_16MB.csv
-
-build_flags =
-    -DBOARD_HAS_PSRAM
-    -DARDUINO_USB_CDC_ON_BOOT=1
-    ; LVGL (also when compiled as a library) picks up include/lv_conf.h of this project
-    -DLV_CONF_INCLUDE_SIMPLE
-    -Iinclude
-
-; vendor-bundled libraries: ESP32_Display_Panel 0.1.4, ESP32_IO_Expander 0.0.2, lvgl 8.3.11
-lib_extra_dirs = ../../2-Program Example/Demo_Arduino/library
-
-upload_port = COM21
-monitor_port = COM21
-monitor_speed = 115200
-monitor_filters = esp32_exception_decoder
+; JC3636W518 — ESP32-S3R8, 16 MB QIO flash, 8 MB OPI PSRAM, 360x360 ST77916 QSPI + CST816S
+; Settings mirror the vendor Arduino IDE setup (2-Program Example/Demo_Arduino/docs/Arduino set up.png)
+
+[env:jc3636w518]
+; pioarduino = Arduino core 3.0.5 (ESP32_Display_Panel 0.1.4 needs core 3.x)
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/51.03.05/platform-espressif32.zip
+board = esp32-s3-devkitc-1
+framework = arduino
+
+board_build.arduino.memory_type = qio_opi
+board_build.flash_mode = qio
+board_upload.flash_size = 16MB
+; GIF compiled into firmware -> 3.4 MB, too big for huge_app (3 MB); 6.25 MB app slots
+board_build.partitions = default_16MB.csv
+
+; optimise for speed instead of size (faster GIF decoding)
+build_unflags = -Os
+build_flags =
+    -O2
+    -DBOARD_HAS_PSRAM
+    -DARDUINO_USB_CDC_ON_BOOT=1
+    ; LVGL (also when compiled as a library) picks up include/lv_conf.h of this project
+    -DLV_CONF_INCLUDE_SIMPLE
+    -Iinclude
+
+; vendor-bundled libraries: ESP32_Display_Panel 0.1.4, ESP32_IO_Expander 0.0.2, lvgl 8.3.11
+lib_extra_dirs = ../../2-Program Example/Demo_Arduino/library
+
+upload_port = COM21
+monitor_port = COM21
+monitor_speed = 115200
+monitor_filters = esp32_exception_decoder
diff --git a/10-OBD-Display-2024/display_gif_embedded/src/main.cpp b/10-OBD-Display-2024/display_gif_embedded/src/main.cpp
index 4eccda6..7afb460 100644
--- a/10-OBD-Display-2024/display_gif_embedded/src/main.cpp
+++ b/10-OBD-Display-2024/display_gif_embedded/src/main.cpp
@@ -12,6 +12,30 @@ const char* password = "123456789";
 
 String httpGETRequest(const char* serverName);
 
+// FPS measurement: LVGL calls this after every screen refresh (= one GIF frame here)
+static volatile uint32_t refr_count = 0;
+static volatile uint32_t refr_time_ms = 0;
+static uint32_t busy_us = 0;  // time spent inside lv_timer_handler()
+
+static void refr_monitor_cb(lv_disp_drv_t* drv, uint32_t time, uint32_t px) {
+  refr_count++;
+  refr_time_ms += time;
+}
+
+void print_fps() {
+  static uint32_t last_ms = 0;
+  uint32_t now = millis();
+  if (now - last_ms < 1000) return;
+  // decode = busy time not spent refreshing the screen (mostly GIF decoding)
+  Serial.printf("FPS: %.1f  avg refresh: %lu ms  avg decode: %lu ms\n", refr_count * 1000.0f / (now - last_ms),
+                refr_count ? refr_time_ms / refr_count : 0,
+                refr_count ? (busy_us / 1000 - refr_time_ms) / refr_count : 0);
+  refr_count = 0;
+  refr_time_ms = 0;
+  busy_us = 0;
+  last_ms = now;
+}
+
 
 void my_print(const char* buf) {
   Serial.println(buf);  // Print logs to the serial monitor
@@ -106,6 +130,7 @@ void setup() {
   delay(200);
   Serial.begin(115200);
   scr_lvgl_init();
+  lv_disp_get_default()->driver->monitor_cb = refr_monitor_cb;
 
   lv_init();
 
@@ -143,15 +168,11 @@ void setup() {
 }
 
 void loop() {
+  uint32_t t0 = micros();
   lv_timer_handler();
-  vTaskDelay(5);
-
-  lv_mem_monitor_t mem_mon;
-  lv_mem_monitor(&mem_mon);
-  printf("Free memory: %d bytes\n", mem_mon.free_size);
-
-  Serial.print("Available Heap: ");
-  Serial.println(esp_get_free_heap_size());
+  busy_us += micros() - t0;
+  vTaskDelay(1);
+  print_fps();
 
 
   // if (WiFi.status() == WL_CONNECTED) {
diff --git a/CLAUDE.md b/CLAUDE.md
index 1530ba1..e500219 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -96,6 +96,11 @@ Cheap dual-mode clones typically expose BLE service `FFF0` (notify `FFF1`, write
 ## Gotchas / observations
 - **LVGL GIF bug (patched locally):** LVGL 8.3.11 `gifdec.c` (`gd_open_gif`) filled the canvas *opaque* with the GIF's background color. GIFs with a transparent background (e.g. `loligod.gif`, bg = RGB 28,29,49) showed that dark gray except where "restore to background" frames had cleared to transparent (→ screen black). **Patched** in the vendor copy `2-Program Example/Demo_Arduino/library/lvgl/src/extra/libs/gif/gifdec.c`: initial canvas alpha 0x00 (marked `LOCAL PATCH`). Re-apply if LVGL is ever replaced/upgraded.
 - Most GIFs in `assets/gifs` are optimized (transparent unchanged pixels, disposal 1/2); `loligod.gif` has a fully transparent background (~84 % of each frame).
+- **GIF performance** (360×360 loligod, embedded, measured with a `monitor_cb` FPS counter in `display_gif_embedded`):
+  baseline 15.4 fps (decode 27 ms + refresh 31 ms) → no LVGL log / no per-loop prints: no change → `vTaskDelay(1)`: 16.5 → **double draw buffer** (2×72 rows internal RAM): 19.5 (refresh 21 ms) → **`-O2`** instead of `-Os`: **20.6 fps** (refresh 19 ms, decode ~24 ms). GIF's own rate is 23.7 fps. From SD card it was only ~1.4 fps.
+  Remaining limit is LVGL's single-threaded GIF decode; going further would need decoding on the other core or a lighter format (e.g. pre-converted frames/MJPEG).
+- **SD card (user's 487 MB SDSC)** intermittently fails to init (`sdmmc_init_ocr ... 0x107`) after resets; once stuck only a power cycle helps (card VDD is hard-wired to 3V3). Recommend a newer SDHC card.
+- Reading boot logs: USB-CDC — reset via DTR=0/RTS pulse, then reopen the port (it re-enumerates).
 - LVGL version: all JC3636W518 projects use the vendor-bundled **LVGL 8.3.11**. LVGL 9 would require porting `scr_st77916.h` (display/touch driver glue).
 - Display is round: corners of the 360×360 framebuffer are not visible — design UI within a 360 px circle.
 - Compiling a 13.9 MB GIF into the firmware will not fit "Huge APP" (3 MB); large media should live on SD (or in a custom partition).