Magento 2 memory leak perfomance

Question

I have a problem with the import data process. First: I have used the factory creator to create a Model set data and save but the problem when I have 400k Item to save.

--- Constructor

\Magento\Sales\Model\OrderFactory $orderFactory

$this->orderFactory = $orderFactory;

--- Process Function (100 item of row) //Another function have 400k row.

public function process($data){
    foreach($data as $row){
         $order = $this->orderFactory->create();
         $order->setData($row);
         $order->save();
    }
}

--- Memory usage;

Memory Usage: 8=1.89402008057 (0)

Memory Usage: 3846.87700 (200k Item)

I'm trying to improve that process using create 1 Object of the Model.

--- Constructor

\Magento\Sales\Model\OrderFactory $orderFactory

$this->order = $orderFactory->create();

--- Process Function

public function process($data){
    foreach($data as $row){
         $order = $this->order->clearInstance();
         $order->unsetData(null);
         $order->setData($row);
         $order->save();
    }
}

Memory usage was reduce.

Memory Usage: 881.244 (0)

Memory Usage: 2146.8836288 (300k).

---- About 100 items was used 1.1M of the memory

Memory Usage: 2125.8544769287 (260k)

Memory Usage: 2126.9217758179 (260100)

Any tips for reducing memory usage to create Magento 2 Model. Instead of the insert to the database using Mysql query.

Thank for any tip.