By Michael Oleaga (staff@latinospost.com) | First Posted: Aug 17, 2012 08:57 AM EDT

With the 13-inch MacBook with Retina display rumored to launch in September, next to the iPhone 5, the 15-inch MacBook Retina has already offered a new upgrade, while users has noticed problems.

Mac's upgrade supplier Other World Computing (OWC) released a new solid-state drive (SSD) for the newest MacBook models. The new SSD gives users more storage space from the traditional 256GB SSD in a standard 15-inch Retina MacBook Pro to 480GB with the OWC upgrade.

The upgrade doesn't come cheap. It is priced at $579. An upside to the heavy price is with the purchase, you get an USB 3.0 to store items used in the old 256 GB drive. A 3-year limited warranty is also provided if purchased here.

The upgrade comes as KGI Securities analyst Ming-Chi Kuo said Apple was preparing a 13-inch Retina MacBook Pro for a September launch. Credibility has been given to Kuo before, as he predicted Apple's decision to abandon the 17-inch MacBook Pro models.

But Apple might need to fix another problem before launching the 13-inch MacBook. Users have complained about the new operating system (OS) Mountain Lion.

Some users wrote on Apple's discussion board with the following:

According to CNET, AnandTech reported a "notable decrease in interface performance" for some of the applications.

CNET's Topher Kessler provided a few suggestions users can try:

Run a general maintenance routine: OS X will create a number of temporary caches and hardware settings can be cleared using a general maintenance routine to see if they are affecting the system's performance or compatibility.

Turn off automatic graphics switching: To conserve power, Apple provides an option to tap into the Intel HD graphics on the CPU or automatically switch to the dedicated Nvidia Geforce 650M GPU. When there is no demand for the faster processor the system will by default switch to the lower power Intel HD graphics, but this may also contribute to perceived lag. Therefore, go to the Energy Saver system preferences and uncheck the automatic graphics switching option to only use the dedicated GPU. You can also use the popular utility to customize which GPU is used and when.

Format and reinstall OS X: Some of those with this problem have tried reinstalling OS X directly but have not seen much improvement; however, some who have performed a full format of their hard drives and then reinstalled OS X from scratch have seen a notable improvement in the interface lag. Therefore, if you are experiencing this problem, you can try first backing up your system and then restart with Command-R held down to load the OS X tools. Then select Disk Utility and use the Erase tab to format the hard drive. When done, quit Disk Utility and proceed with the OS X installation, migrating your data from your backup when the installation is complete.