diff --git a/renderdoc/api/replay/pipestate.inl b/renderdoc/api/replay/pipestate.inl
index 33771ed9b..917fe9c86 100644
--- a/renderdoc/api/replay/pipestate.inl
+++ b/renderdoc/api/replay/pipestate.inl
@@ -1036,6 +1036,12 @@ rdcarray<BoundResourceArray> PipeState::GetReadOnlyResources(ShaderStage stage)
     {
       const D3D12Pipe::Shader &s = GetD3D12Stage(stage);
 
+      size_t size = 0;
+      for(int space = 0; space < s.spaces.count(); space++)
+        size += s.spaces[space].srvs.size();
+
+      ret.reserve(size);
+
       for(int space = 0; space < s.spaces.count(); space++)
       {
         for(int reg = 0; reg < s.spaces[space].srvs.count(); reg++)
@@ -1087,6 +1093,12 @@ rdcarray<BoundResourceArray> PipeState::GetReadOnlyResources(ShaderStage stage)
 
       ShaderStageMask mask = MaskForStage(stage);
 
+      size_t size = 0;
+      for(int set = 0; set < descsets.count(); set++)
+        size += descsets[set].bindings.size();
+
+      ret.reserve(size);
+
       for(int set = 0; set < descsets.count(); set++)
       {
         const VKPipe::DescriptorSet &descset = descsets[set];
@@ -1179,6 +1191,12 @@ rdcarray<BoundResourceArray> PipeState::GetReadWriteResources(ShaderStage stage)
     {
       const D3D12Pipe::Shader &s = GetD3D12Stage(stage);
 
+      size_t size = 0;
+      for(int space = 0; space < s.spaces.count(); space++)
+        size += s.spaces[space].uavs.size();
+
+      ret.reserve(size);
+
       for(int space = 0; space < s.spaces.count(); space++)
       {
         for(int reg = 0; reg < s.spaces[space].uavs.count(); reg++)
@@ -1226,6 +1244,12 @@ rdcarray<BoundResourceArray> PipeState::GetReadWriteResources(ShaderStage stage)
 
       ShaderStageMask mask = MaskForStage(stage);
 
+      size_t size = 0;
+      for(int set = 0; set < descsets.count(); set++)
+        size += descsets[set].bindings.size();
+
+      ret.reserve(size);
+
       for(int set = 0; set < descsets.count(); set++)
       {
         const VKPipe::DescriptorSet &descset = descsets[set];