diff --git a/rpcs3/Emu/RSX/D3D12/D3D12Buffer.cpp b/rpcs3/Emu/RSX/D3D12/D3D12Buffer.cpp
index 9b6a2f2d3f..e4ad9e3e22 100644
--- a/rpcs3/Emu/RSX/D3D12/D3D12Buffer.cpp
+++ b/rpcs3/Emu/RSX/D3D12/D3D12Buffer.cpp
@@ -348,7 +348,7 @@ std::pair<std::vector<D3D12_VERTEX_BUFFER_VIEW>, D3D12_INDEX_BUFFER_VIEW> D3D12G
 			indexCount = 6 * m_indexed_array.m_data.size() / (4 * indexSize);
 		else
 			indexCount = m_draw_array_count * 6 / 4;
-		size_t subBufferSize = indexCount * indexSize;
+		size_t subBufferSize = powerOf2Align(indexCount * indexSize, 64);
 		// 65536 alignment
 		size_t bufferHeapOffset = getCurrentResourceStorage().m_vertexIndexBuffersHeapFreeSpace;
 		bufferHeapOffset = (bufferHeapOffset + 65536 - 1) & ~65535;
@@ -366,7 +366,7 @@ std::pair<std::vector<D3D12_VERTEX_BUFFER_VIEW>, D3D12_INDEX_BUFFER_VIEW> D3D12G
 		void *bufferMap;
 		check(indexBuffer->Map(0, nullptr, (void**)&bufferMap));
 		if (indexed_draw && !m_forcedIndexBuffer)
-			memcpy(bufferMap, m_indexed_array.m_data.data(), subBufferSize);
+			streamBuffer(bufferMap, m_indexed_array.m_data.data(), subBufferSize);
 		else if (indexed_draw && m_forcedIndexBuffer)
 		{
 			switch (m_indexed_array.m_type)
diff --git a/rpcs3/Emu/RSX/D3D12/D3D12GSRender.cpp b/rpcs3/Emu/RSX/D3D12/D3D12GSRender.cpp
index 40c11e0072..d812a05350 100644
--- a/rpcs3/Emu/RSX/D3D12/D3D12GSRender.cpp
+++ b/rpcs3/Emu/RSX/D3D12/D3D12GSRender.cpp
@@ -41,7 +41,7 @@ void D3D12GSRender::ResourceStorage::Init(ID3D12Device *device)
 	// Create heap for vertex and constants buffers
 	D3D12_HEAP_DESC vertexBufferHeapDesc = {};
 	// 16 MB wide
-	vertexBufferHeapDesc.SizeInBytes = 1024 * 1024 * 16;
+	vertexBufferHeapDesc.SizeInBytes = 1024 * 1024 * 128;
 	vertexBufferHeapDesc.Flags = D3D12_HEAP_FLAG_ALLOW_ONLY_BUFFERS;
 	vertexBufferHeapDesc.Properties.Type = D3D12_HEAP_TYPE_UPLOAD;
 	check(device->CreateHeap(&vertexBufferHeapDesc, IID_PPV_ARGS(&m_vertexIndexBuffersHeap)));