diff --git a/src/bgfx_p.h b/src/bgfx_p.h
index 3246a0261..f91d9a88b 100644
--- a/src/bgfx_p.h
+++ b/src/bgfx_p.h
@@ -4431,18 +4431,16 @@ namespace bgfx
 
 		uint32_t getAvailTransientIndexBuffer(uint32_t _num, uint16_t _indexSize)
 		{
-			const uint32_t offset = bx::strideAlign(m_iboffset, _indexSize);
-			uint32_t iboffset = offset + _num*_indexSize;
-			iboffset = bx::min<uint32_t>(iboffset, g_caps.limits.maxTransientIbSize);
-			const uint32_t num = (iboffset-offset)/_indexSize;
-			return num;
+			const uint64_t offset   = bx::strideAlign(m_iboffset, _indexSize);
+			const uint64_t iboffset = bx::min<uint64_t>(offset + uint64_t(_num)*_indexSize, g_caps.limits.maxTransientIbSize);
+			return uint32_t(bx::max(iboffset, offset) - offset)/_indexSize;
 		}
 
 		uint32_t allocTransientIndexBuffer(uint32_t& _num, uint16_t _indexSize)
 		{
-			uint32_t offset = bx::strideAlign(m_iboffset, _indexSize);
-			uint32_t num    = getAvailTransientIndexBuffer(_num, _indexSize);
-			m_iboffset = offset + num*_indexSize;
+			const uint32_t offset = bx::strideAlign(m_iboffset, _indexSize);
+			const uint32_t num    = getAvailTransientIndexBuffer(_num, _indexSize);
+			m_iboffset = 0 == num ? m_iboffset : offset + num*_indexSize;
 			_num = num;
 
 			return offset;
@@ -4450,18 +4448,16 @@ namespace bgfx
 
 		uint32_t getAvailTransientVertexBuffer(uint32_t _num, uint16_t _stride)
 		{
-			uint32_t offset   = bx::strideAlign(m_vboffset, _stride);
-			uint32_t vboffset = offset + _num * _stride;
-			vboffset = bx::min<uint32_t>(vboffset, g_caps.limits.maxTransientVbSize);
-			uint32_t num = (vboffset-offset)/_stride;
-			return num;
+			const uint64_t offset   = bx::strideAlign(m_vboffset, _stride);
+			const uint64_t vboffset = bx::min<uint64_t>(offset + uint64_t(_num)*_stride, g_caps.limits.maxTransientVbSize);
+			return uint32_t(bx::max(vboffset, offset) - offset)/_stride;
 		}
 
 		uint32_t allocTransientVertexBuffer(uint32_t& _num, uint16_t _stride)
 		{
-			uint32_t offset = bx::strideAlign(m_vboffset, _stride);
-			uint32_t num    = getAvailTransientVertexBuffer(_num, _stride);
-			m_vboffset = offset + num * _stride;
+			const uint32_t offset = bx::strideAlign(m_vboffset, _stride);
+			const uint32_t num    = getAvailTransientVertexBuffer(_num, _stride);
+			m_vboffset = 0 == num ? m_vboffset : offset + num*_stride;
 			_num = num;
 
 			return offset;
diff --git a/src/renderer_d3d12.cpp b/src/renderer_d3d12.cpp
index ce2c39f49..f9acb5a56 100644
--- a/src/renderer_d3d12.cpp
+++ b/src/renderer_d3d12.cpp
@@ -5937,6 +5937,11 @@ namespace bgfx { namespace d3d12
 			if (!_finishAll
 			&&  _waitFence <= m_completedFence)
 			{
+				while (0 < m_control.getNumUsed()
+				&&     consume(0) )
+				{
+				}
+
 				return;
 			}
 		}