diff --git a/include/vkd3d.h b/include/vkd3d.h
index 175a278c3f..a7e2ce40ea 100644
--- a/include/vkd3d.h
+++ b/include/vkd3d.h
@@ -111,6 +111,7 @@ extern "C" {
 #define VKD3D_CONFIG_FLAG_INSTRUCTION_QA_CHECKS (1ull << 53)
 #define VKD3D_CONFIG_FLAG_TRANSFER_QUEUE (1ull << 54)
 #define VKD3D_CONFIG_FLAG_NO_GPU_UPLOAD_HEAP (1ull << 55)
+#define VKD3D_CONFIG_FLAG_NO_SUBALLOCATION (1ull << 56)
 
 struct vkd3d_instance;
 
diff --git a/libs/vkd3d/device.c b/libs/vkd3d/device.c
index 2f68fecb41..5f90e96195 100644
--- a/libs/vkd3d/device.c
+++ b/libs/vkd3d/device.c
@@ -982,6 +982,7 @@ static const struct vkd3d_debug_option vkd3d_config_options[] =
     {"instruction_qa_checks", VKD3D_CONFIG_FLAG_INSTRUCTION_QA_CHECKS},
     {"transfer_queue", VKD3D_CONFIG_FLAG_TRANSFER_QUEUE},
     {"no_gpu_upload_heap", VKD3D_CONFIG_FLAG_NO_GPU_UPLOAD_HEAP},
+    {"no_suballocation", VKD3D_CONFIG_FLAG_NO_SUBALLOCATION},
 };
 
 static void vkd3d_config_flags_init_once(void)
diff --git a/libs/vkd3d/memory.c b/libs/vkd3d/memory.c
index 1d62fc2fac..52166023a7 100644
--- a/libs/vkd3d/memory.c
+++ b/libs/vkd3d/memory.c
@@ -1839,6 +1839,9 @@ bool vkd3d_allocate_image_memory_prefers_dedicated(struct d3d12_device *device,
 static bool vkd3d_memory_info_allow_suballocate(struct d3d12_device *device,
         const struct vkd3d_allocate_memory_info *info)
 {
+    if (vkd3d_config_flags & VKD3D_CONFIG_FLAG_NO_SUBALLOCATION)
+        return true;
+
     /* pNext implies dedicated allocation or similar. Host pointer implies external memory import. */
     if (info->pNext || info->host_ptr)
         return false;
@@ -1912,6 +1915,19 @@ HRESULT vkd3d_allocate_memory(struct d3d12_device *device, struct vkd3d_memory_a
         info = &tmp_info;
     }
 
+    /* To avoid a potential collapse in CPU performance, force larger allocations
+     * when using NO_SUBALLOCATION. */
+    if ((vkd3d_config_flags & VKD3D_CONFIG_FLAG_NO_SUBALLOCATION) &&
+            !info->host_ptr &&
+            (info->flags & VKD3D_ALLOCATION_FLAG_GLOBAL_BUFFER) &&
+            info->memory_requirements.size < VKD3D_VA_BLOCK_SIZE)
+    {
+        if (&tmp_info != info)
+            tmp_info = *info;
+        info = &tmp_info;
+        tmp_info.memory_requirements.size = max(VKD3D_VA_BLOCK_SIZE, tmp_info.memory_requirements.size);
+    }
+
     if (suballocate)
         hr = vkd3d_suballocate_memory(device, allocator, info, allocation);
     else