diff --git a/drivers/display/display_nrf_led_matrix.c b/drivers/display/display_nrf_led_matrix.c
index 0d8bac33491..52b6dc4f70e 100644
--- a/drivers/display/display_nrf_led_matrix.c
+++ b/drivers/display/display_nrf_led_matrix.c
@@ -60,13 +60,15 @@ LOG_MODULE_REGISTER(nrf_led_matrix, CONFIG_DISPLAY_LOG_LEVEL);
 DT_FOREACH_PROP_ELEM(MATRIX_NODE, pixel_mapping, CHECK_PIXEL)
 
 #define REFRESH_FREQUENCY  DT_PROP(MATRIX_NODE, refresh_frequency)
-#define BASE_FREQUENCY     16000000
-#define TIMER_CLK_CONFIG   NRF_TIMER_FREQ_16MHz
-#define PWM_CLK_CONFIG     NRF_PWM_CLK_16MHz
+#define BASE_FREQUENCY     8000000
+#define TIMER_CLK_CONFIG   NRF_TIMER_FREQ_8MHz
+#define PWM_CLK_CONFIG     NRF_PWM_CLK_8MHz
 #define BRIGHTNESS_MAX     255
 
-#define QUANTUM  (BASE_FREQUENCY / (REFRESH_FREQUENCY * BRIGHTNESS_MAX * \
-				    PIXEL_COUNT * GROUP_SIZE))
+/* Always round up, as even a partially filled group uses the full time slot. */
+#define PIXEL_SLOTS   (ROW_COUNT * NRFX_CEIL_DIV(COL_COUNT, GROUP_SIZE))
+#define QUANTUM       (BASE_FREQUENCY \
+		       / (REFRESH_FREQUENCY * PIXEL_SLOTS * BRIGHTNESS_MAX))
 #define PIXEL_PERIOD  (BRIGHTNESS_MAX * QUANTUM)
 #if (PIXEL_PERIOD > BIT_MASK(16)) || \
     (USE_PWM && PIXEL_PERIOD > PWM_COUNTERTOP_COUNTERTOP_Msk)