$batch_insert = [];
$batch_size = 1000; // can be lower / higher number, set as needed
$processed = 0; // keep count of how many items have already been run

if(isset($batch_insert[$processed + $batch_size])) {

}
while($i <

$data = array(
    array('user_id'=>'Coder 1', 'subject_id'=> 4096),
    array('user_id'=>'Coder 2', 'subject_id'=> 2048),
    //...
);

Model::insert($data); // Eloquent approach
DB::table('table')->insert($data); // Query Builder approach