Running out of space after upgrading memory. Hard Drives & RAM: Storage vs. Performance

We hear it often. “I just upgraded my memory, so how I can I be running out of space?” Do you know what an SSD is versus a SATA Drive? Or what it was you upgraded when you added memory to your Mac awhile ago? Apple is increasingly shipping more Macs (specifically Macbook Air laptops) with solid state drives (SSDs), and many users may not realize what it means to have an SSD versus a SATA drive. Why should you care? Because it’s all about your data. Often it’s not until a laptop runs out of space that the hard drive is given much thought. At that point. the proud owner of a fairly new Mac usually complains that the Mac was purchased with “a LOT of memory”, and is surprised space has run out.

I should explain that operational memory (RAM) is very different from storage memory (hard drive space). Although both use the same measurement format (megs and gigs), they are not the same. More RAM allows the computer to process more calculations at the same time. Think of the size of RAM as being room for the computer to work. The higher the RAM number (4 Gigs instead of 1 Gig), the faster the performance of the computer system. I’ve found that the amount of RAM can even be more important than processor speed itself. Our trusty G5 Tower here in the office had no trouble keeping up with a “faster”, yet less-endowed-with-RAM Intel Mac. Even though the processor (brain) of the G5 is technically slower, the 12 Gigs of RAM available to it allows it to process more data than an Intel Mac with a much faster processor, but only 2 Gigs of RAM. Increasing RAM is the easiest way for a user to improve the performance of his computer. Period. Most computer systems allow for the addition of at least one, larger or equal RAM chip. (See our article on RAM upgrades, coming soon).

The higher the Gig number of a hard drive (500 gigs instead of 160 gigs), the more data or files a drive can hold. For most laptops, the addition of memory refers to RAM (Random Access Memory), not Gigabytes of hard drive space. The addition of RAM is fairly simple and involves a few chips or mini circuit boards that are plugged in to slots. The addition of hard drive space requires replacing an existing hard drive for a larger one. RAM you may be able to add yourself. Hard drive, maybe not. Get a pro to help you.

So what are hard drives anyway? People may lament that theirs “crashed,” but it’s likely they couldn’t tell you how it works. Why should you care? Simply put, the hard drive houses ALL of your data. Every document, every application, photo, song, and your operating system too. Without that drive, your computer is toast – an assembly of parts without any instruction. Lose that drive, and you’ve lost it all, unless you have a copy or backup of your data somewhere.


A hard drive is a box that holds a sandwich of highly-polished, electromagnetic disks. These disks spin at varying speeds, almost all the time you’re using it. A standard speed for laptop hard drives was 5400 rpm (revolutions per minute), and is considered “ok”. A better, newer standard, is 7200 rpm. The faster the spin rate, the faster the hard drive can offer up data stored on it, which translates into better performance. Higher speeds are more desirable, and more expensive. (Not that long ago, drives that could maintain a spin rate of 10,000 rpm cost over $1,000 each). The challenge comes when we reach a trade-off between storage capacity of a drive, and the spin rate (rpm). The larger a drive gets, the more difficult it is to spin and read data from those disks accurately. Depending on the specs, a one terabyte (1TB) drive will operate more efficiently and faster than a 2 TB drive.

The capacity + speed + accuracy = expensive engineering and production. While a three terabyte (3x 1,000 megs) hard drive seems very desirable because of it’s size, that drive may be considerably slower than a 1 TB drive, and will thus slow down computer operation. Three TB drives generally run at 5900 RPM, while 1 TB drives usually run at 7200 RPM. One would want to get the best trade-off and return for ones investment, and match the capacity to required performance.

If we put a very large drive into an older Mac , performance could suffer because larger drives spin at 5900 rpm, and not 7200 rpm, like the 1 and 2 TB drives. Another issue is whether an older Mac can even recognize a large drives. Some older Macs cannot, but that’s another topic. A common mistake people make is to replace an original hard drive with the largest drive they can find. Their computers then become so sluggish that the users want to throw it through a window.

In short, we want to consider performance AND storage capacity when upgrading a Mac.

Enter the Solid State Drive. As it’s name implies, the SSD has no moving parts, thus there is NO spin rate. The SSD is a collection of silicone chips that have been assembled in an array, much like the USB flash drives we have all come to use and love for moving files between computers. While they have dropped in price considerably, SSDs are still much more expensive than the standard SATA drives. A 500 Gig SSD option currently runs $500 at Apple, while a 1,000 Gig SATA drive, with twice the capacity, runs about $110 at your local Best Buy store. If you do some minimum shopping around, 1 TB drives can be had for under $100. iMacs still sport 1TB SATA drives as a standard, but a second, smaller and faster internal SSD drive can be ordered for that iMac now – straight from the factory.

So why go SSD? Speed, space and weight. Apple builds all of its Macbook Air laptops with SSDs in them. The thin form factor, and light weight, require it. This also limits how much storage space is on those machines – currently a maximum of 500 Gigs. iPads and iPhones too have a form of SSDs built into them, which accounts for their speed, expense and limits to capacity.

Some die-hard fans of performance boosting modifications install Solid State drives in their towers (G5s and Mac Pros). An SSD configured properly in a tower allows it to boot up much more quickly, and applications to really snap to attention. Still, if you’re not an expert with manipulating operating systems from a variety of sources, you may want to reconsider trying this at home. It’s easy to get confused, not backup what you think you’re backing up, etc. There are other limitations too, and you have to be knowledgeable to set up necessary work-arounds.

And finally, there is much debate around which type of drive, the more traditional SATA drive, or the newly “standardized” SSD, is best in a recovery situation. Currently, the recovery of data from a crashed SATA or IDE drive is more likely to be successful than from an SSD. In the case of SATA or IDE (the two older types of drives found in most computers today), a hard drive “crash” usually involves failure of a slider or drive head (think needle of a phonograph), the motor that spins (called the “spindle”), or the controller card that controls communication between the drive and a computer connected to it. Replacing the spindle, re-calibrating or replacing the head, and / or the controller card often allows for full recovery. That sort of work remains the domain of specialists like DriveSavers, and is not something you would or should attempt. But the point is, if you have the budget, at least some data recovery is likely.

SSDs, on the other hand, employ chips. Depending on the damage, and because of the technology used to store data on them, data recovery from solid state drives is less likely. As a rule, we rely on SATA drives here in our office, and use SSDs as temporary, even experimental storage media. We assume the data on SSDs is transient, and backup to SATA drives. That USB flash drive on your keychain? Make sure the data on it exists somewhere else. USB flash drives can fail too.

To sum things up, before you rush out to take advantage of a performance-boosting Solid State Drive for your system then, think it over. And, if you are lucky enough to own a Macbook Air with a 500 gig SSD in it, make sure you have a regularly scheduled backup configured for it. Time machine will do that for you of course, but only if you set it up with a backup drive. It’s up to you.