Many Magento issues are caused by slow performance. The recommended way to speed up Magento’s performance is to enable its Compilation function. The performance increase is between 25%-50% on page loads. In order to use this tool, the directory ‘includes’ and the file ‘includes/config.php’ must both be writable.
Important: Before you make any changes to your Magento installation you should always disable compilation. Once the changes are made, run the compilation process, and then enable it.
Please following the steps:
Step 1: Clear your cache.
Step 2: You can enable Magento Compilation from your Magento admin panel > System > Tools > Compilation.
Step 3: Click the “Run Compilation Process” button, it will give you a message that it compiled successfully. Go on to the next step.
Step 4: Then go clear your cache again.