diff --git a/src/config.c b/src/config.c
index 86d80958..a7d52a84 100644
--- a/src/config.c
+++ b/src/config.c
@@ -368,7 +368,7 @@ static int config_parse(config *cfg, const char *name, const char *value)
   {
     int rdo = 0;
     if (sscanf(value, "%d", &rdo)) {
-      if (rdo < 0 || rdo > 2) {
+      if (rdo < 0 || rdo > 3) {
         fprintf(stderr, "--rd parameter out of range [0..2], set to 1\n");
         rdo = 1;
       }
diff --git a/src/global.h b/src/global.h
index 6476d3d0..df74c657 100644
--- a/src/global.h
+++ b/src/global.h
@@ -60,11 +60,19 @@ typedef int16_t coefficient;
 //spec: references to variables defined in Rec. ITU-T H.265 (04/2013)
 
 //Search depth for intra and inter. Block sizes: 0 => 64x64, 1 => 32x32, 2 => 16x16, 3 => 8x8, 4 => 4x4
-#define MAX_INTER_SEARCH_DEPTH 3
-#define MIN_INTER_SEARCH_DEPTH 0
+#ifndef MAX_INTER_SEARCH_DEPTH
+#   define MAX_INTER_SEARCH_DEPTH 3
+#endif
+#ifndef MIN_INTER_SEARCH_DEPTH
+#   define MIN_INTER_SEARCH_DEPTH 0
+#endif
 
-#define MAX_INTRA_SEARCH_DEPTH 4
-#define MIN_INTRA_SEARCH_DEPTH 1
+#ifndef MAX_INTRA_SEARCH_DEPTH
+#   define MAX_INTRA_SEARCH_DEPTH 4
+#endif
+#ifndef MIN_INTRA_SEARCH_DEPTH
+#   define MIN_INTRA_SEARCH_DEPTH 0
+#endif
 
 // Maximum CU depth when descending form LCU level.
 #define MAX_DEPTH 3  /*!< spec: log2_diff_max_min_luma_coding_block_size */
diff --git a/src/rdo.c b/src/rdo.c
index 480dd773..78106fe2 100644
--- a/src/rdo.c
+++ b/src/rdo.c
@@ -170,7 +170,7 @@ uint32_t rdo_cost_intra(encoder_state * const encoder_state, pixel *pred, pixel
       }
       cost += (1 + coeffcost + (coeffcost>>1))*((int)encoder_state->global->cur_lambda_cost+0.5);
       // Full RDO
-    } else if(encoder->rdo == 2) {
+    } else if(encoder->rdo >= 2) {
       coeffcost = get_coeff_cost(encoder_state, temp_coeff, width, 0, luma_scan_mode);
 
       cost  += coeffcost*((int)encoder_state->global->cur_lambda_cost+0.5);
diff --git a/src/search.c b/src/search.c
index 9e7c1a1c..d83e5f1b 100644
--- a/src/search.c
+++ b/src/search.c
@@ -804,7 +804,7 @@ static int cu_rd_cost_luma(const encoder_state *const encoder_state,
     }
     cost += (coeff_cost + (coeff_cost >> 1)) * (int32_t)(encoder_state->global->cur_lambda_cost + 0.5);
 
-  } else if (rdo == 2) {
+  } else if (rdo >= 2) {
     int coeff_cost = 0;
 
     coefficient coeff_temp[32 * 32];
@@ -890,7 +890,7 @@ static int cu_rd_cost_chroma(const encoder_state *const encoder_state,
     }
 
     cost += (coeff_cost + (coeff_cost >> 1)) * (int32_t)(encoder_state->global->cur_lambda_cost + 0.5);
-  } else if (rdo == 2) {
+  } else if (rdo >= 2) {
     coefficient coeff_temp[16 * 16];
     int8_t scan_order = get_scan_order(pred_cu->type, pred_cu->intra[0].mode_chroma, depth);
 
@@ -1243,30 +1243,47 @@ static int search_cu_intra(encoder_state * const encoder_state,
   // Get intra predictors
   intra_get_dir_luma_predictor(x_px, y_px, candidate_modes, cur_cu, left_cu, above_cu);
 
+  if (depth > 0) {
   // Build reconstructed block to use in prediction with extrapolated borders
   intra_build_reference_border(encoder_state->encoder_control, x_px, y_px, cu_width * 2 + 8,
                                rec_buffer, cu_width * 2 + 8, 0,
                                frame->width,
                                frame->height,
                                lcu);
+  }
 
   // Find best intra mode for 2Nx2N.
   {
     pixel *ref_pixels = &lcu->ref.y[lcu_px.x + lcu_px.y * LCU_WIDTH];
     unsigned pu_index = PU_INDEX(x_px >> 2, y_px >> 2);
+
     int8_t modes[35];
     uint32_t costs[35];
-    int8_t number_of_modes = search_intra_rough(encoder_state, 
+    int8_t number_of_modes;
+    bool skip_rough_search = (depth == 0 || encoder_state->encoder_control->rdo >= 3);
+    if (!skip_rough_search) {
+      number_of_modes = search_intra_rough(encoder_state,
                                                 ref_pixels, LCU_WIDTH,
                                                 cu_in_rec_buffer, cu_width * 2 + 8,
                                                 cu_width, candidate_modes,
                                                 modes, costs);
+    } else {
+      number_of_modes = 35;
+      for (int i = 0; i < number_of_modes; ++i) {
+        modes[i] = i;
+        costs[i] = MAX_INT;
+      }
+    }
 
     // Set transform depth to current depth, meaning no transform splits.
     lcu_set_trdepth(lcu, x_px, y_px, depth, depth);
 
-    if (encoder_state->encoder_control->rdo == 2) {
-      int num_modes_to_check = MIN(number_of_modes, (cu_width <= 8) ? 8 : 3);
+    if (encoder_state->encoder_control->rdo >= 2) {
+      int number_of_modes_to_search = (cu_width <= 8) ? 8 : 3;
+      if (encoder_state->encoder_control->rdo == 3) {
+        number_of_modes_to_search = 35;
+      }
+      int num_modes_to_check = MIN(number_of_modes, number_of_modes_to_search);
       search_intra_rdo(encoder_state, 
                        lcu_px.x, lcu_px.y, depth,
                        ref_pixels, LCU_WIDTH,
@@ -1316,6 +1333,8 @@ static int search_cu(encoder_state * const encoder_state, int x, int y, int dept
     return 0;
   }
 
+  lcu_t *lcu = &work_tree[depth];
+
   cur_cu = &(&work_tree[depth])->cu[LCU_CU_OFFSET+(x_local>>3) + (y_local>>3)*LCU_T_CU_WIDTH];
   // Assign correct depth
   cur_cu->depth = depth > MAX_DEPTH ? MAX_DEPTH : depth;
@@ -1387,7 +1406,7 @@ static int search_cu(encoder_state * const encoder_state, int x, int y, int dept
   }
 
   // Recursively split all the way to max search depth.
-  if (depth < MAX_INTRA_SEARCH_DEPTH || depth < MAX_INTER_SEARCH_DEPTH) {
+  if (depth < MAX_INTRA_SEARCH_DEPTH || (depth < MAX_INTER_SEARCH_DEPTH && encoder_state->global->slicetype != SLICE_I)) {
     int half_cu = cu_width / 2;
     // Using Cost = lambda * 9 to compensate on the price of the split
     int split_cost = (int)(encoder_state->global->cur_lambda_cost + 0.5) * 9;
diff --git a/src/transform.c b/src/transform.c
index bdcdfdc2..21f2bb3e 100644
--- a/src/transform.c
+++ b/src/transform.c
@@ -540,7 +540,7 @@ int quantize_residual_trskip(
     // Estimate bit cost of encoding the coeffs as ~(1.5 * abs_sum).
     unsigned abs_coeffs = coefficients_calc_abs(noskip.coeff, 4, 4);
     noskip.cost += (abs_coeffs + (abs_coeffs / 2)) * bit_cost;
-  } else if (encoder_state->encoder_control->rdo == 2) {
+  } else if (encoder_state->encoder_control->rdo >= 2) {
     noskip.cost += get_coeff_cost(encoder_state, noskip.coeff, 4, 0, scan_order) * bit_cost;
   }
 
@@ -558,7 +558,7 @@ int quantize_residual_trskip(
       // Estimate bit cost of encoding the coeffs as ~(1.5 * abs_sum + 1).
       unsigned abs_coeffs = coefficients_calc_abs(skip.coeff, 4, 4);
       skip.cost += (1 + abs_coeffs + (abs_coeffs / 2)) * bit_cost;
-    } else if (encoder_state->encoder_control->rdo == 2) {
+    } else if (encoder_state->encoder_control->rdo >= 2) {
       skip.cost += get_coeff_cost(encoder_state, skip.coeff, 4, 0, scan_order) * bit_cost;
     }
   }