title: LightGBM very slow on AWS but not locally
body: <p>I have a i7 9700 CPU @ 3.00GHz on my local machine and I am able to tune and train my LightGBM model in around 5 hours. When I repeat the procedure on an AWS EC2 instance, <a href="https://aws.amazon.com/about-aws/whats-new/2019/06/introducing-new-instance-sizes-for-amazon-ec2-c5-instances/" rel="nofollow noreferrer">c5.12xlarge</a>, I see a significantly slower training time and it can take up to 20 hours to complete the tuning procedure.</p>
  
  <p>The dataset I use has around 20 features and 2 million rows and this is the parameter I use for the model:</p>
  
  <pre><code> model_params = {"boosting_type": "gbdt",
                   "num_threads": 16,
                   "colsample_bytree": 0.51,
                   "importance_type": "split",
                   "learning_rate": 0.1,
                   "max_depth": -1,
                   "min_child_samples": 35,
                   "min_child_weight": 0.001,
                   "min_split_gain": 0.11,
                   "n_estimators": 5000,
                   "num_leaves": 412,
                   "objective": "regression_l1",
                   "random_state": 1337,
                   "reg_alpha": 0.3,
                   "reg_lambda": 3.5,
                   "subsample": 0.59,
                   "subsample_for_bin": 200000,
                   "subsample_freq": 0,
                   "verbose": -1}
  </code></pre>
  
  <p>What should I do to increase the performance on AWS?</p>