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Diagnosing a slow running Mac – Part 3: Storage

Posted on September 5, 2010 by Clive Sweeting

This short series will discuss some of the common problems that can slow your Mac down dramatically. In this installment we’ll look at hard drive performance.

If you’ve eliminated RAM and processor performance, then the next thing to look at is the hard drive. For just about every action you ask the computer to do, it has to read or write data to the hard drive. This is, in computer terms, extremely slow. So if you are using Photoshop, Final Cut, InDesign or other programs that extensively use the disk, you will often find that you have RAM to spare, the CPU is barely ticking over, but the machine feels unresponsive because it’s thrashing the hard drive. So what can you do to improve this?

  1. Make sure that you have at least 20 GB of free disk space, more if you can. Hard drives slow down as they get more full, as continuous sections of free space get harder to find, and data gets written to the inner, slower sections of disk. Don’t de-fragment – get a bigger disk.
  2. Check the disk for errors using Disk Utility or another tool. Repair if necessary.
  3. Check the system.log for disk I/O. If you see any backup your entire drive and replace it at the first opportunity.
  4. Get a faster drive. You can achieve this in any number of ways, spending from £50 to many thousands.

The easiest and cheapest option is to just replace the internal drive with a faster speed drive. So if you have a 5400rpm drive, get a 7200 rpm, 100oo rpm or 15000 rpm model. The next option is to get a faster drive by setting up a RAID 0 “Striped” array. Personally I think you’re nuts if you do this without a rock solid backup system. My preferred option is to replace the startup disk with a Solid State Disk (SSD).

SSDs can be massively faster if you choose your model carefully. Apple do supply Configure To Order (CTO) MacBooks and iMacs with SSDs, but they don’t have a history of fitting the highest performing models. My advice is to buy your own SSD and fit it yourself. As of now, the rule is buy an Intel X25 model or a brand using a “Sandforce” controller to get the best performance. The greatest perceived improvement will be seen by MacBook owners.

Because SSD drives are so hideously expensive, most people dismiss them as an option as they don’t offer enough storage. However, I’m currently fitting an internal SSD into my MacBook Pro, giving me a 64GB SSD boot drive and a 250GB SATA drive that replaces the Superdrive. This means my MacBook has 2 internal drives, one screamingly fast that runs OS X, applications and scratch space, the other hold much of my data.

Looking for a professional SSD upgrade service for your MacBook Pro, Mac Pro or iMac? What to fit an extra internal hard drive to your MacBook Pro? Please get in touch…

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Diagnosing a slow running Mac – Part 2: Processor

Posted on September 1, 2010 by Clive Sweeting

This short series will discuss some of the common problems that can slow your Mac down dramatically. In this installment we’ll look at processor performance, also known as the CPU.

If you’ve eliminated low RAM as the major reason your Mac is running slow, the next thing to look at is processor power. When people talk about getting a “faster computer”, they are almost invariably talking about getting a quicker processor. However in my experience much of the time this isn’t the problem, unless they are playing games, doing hardcore video editing or computational programming.

So how do you know if your processor is slowing you down? Easy. Open Activity Monitor, click in the “% CPU” column and keep an eye on which Processes are taking more than 50%. If you have a machine with multiple processors you should be seeing programs taking more than 100%. Sounds weird, but each processor core is considered 100%, so if you have a Quad-core machine you have a theoretical 400% to play with. If you click into the CPU tab, you can see a historical activity chart showing processor utilisation per core. If these are consistently high, you machine is CPU performance bound.

The only option in this instance is to get a machine with greater performance. Either a faster processor or more processor cores.

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Diagnosing a slow running Mac – Part 1: Memory

Posted on August 27, 2010 by Clive Sweeting

This short series will discuss some of the common problems that can slow your Mac down dramatically. In this installment we’ll look at memory, also known as RAM.

Over the years I’ve had probably hundreds of people say to me “my Mac’s running slowly, should I get a new one?”. Typically they’ll have gone to one of the Apple Mac retailers in Bath or Bristol to buy a Mac and had the virtues of the latest Macs extolled to them, and left with the warm glow of certainty that spending lots of money with transform their lives.

Sometimes this is true. Newer, faster hardware may be the solution. But often it’s not the whole story. There are a large number of factors that control the perceived performance of a computer and working out which is the “Rate Limiting Step”, to borrow a phrase from chemistry, can go a way to getting better performance from what you already have.

So how do you know if I have too little memory? The surest sign is that when you have a number of programs open, when you try to switch between them the computer grinds to a halt as the hard drive thrashes noisily. So what’s going on?

For every program that you have open, the Mac has to put aside space to remember what the program is doing. If it can it’ll use free space in the RAM (the ultra-fast short term memory of the computer). If there is not enough free space in RAM, it’ll write it to the hard disk, which is many many times slower. Think in these terms: when you go shopping, often you can remember what you want in your head and recalling is almost instantaneous. But sometimes your shipping list is too big to remember; so you have to write it down, then read it to remember what you wanted. Much, much, much slower. When you have insufficient RAM, you Mac will constantly be writing information to the hard disk, which is slow.

You can use the Activity Monitor application to see how much RAM programs are gobbling and how much the hard disk is being thrashed. Look in the System Memory tab and see how much “Free” memory you have and particularly look to see if the “Page Outs” increases over time. “Page Outs” indicates how frequently the computer is having to use swap space instead of RAM.

If the answer is a lot, try closing the programs that gobble the most RAM. Everything runs quicker? Then you need to buy more RAM…

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Save money with iStockPhoto credit codes

Posted on August 27, 2010 by Clive Sweeting

If like me, you provide web design services to clients in and around Bradford on Avon, Trowbridge, Bath or Bristol, you’re probably spending a fair amount of time looking for good images to make your web design stand out. You’ll also find that fairly soon it feels like you’re giving iStockPhoto the keys to your bank account, as they’ve aggressively been increasing prices since Getty bought them.

But never fear, if you search around, you can often find some fairly tasty discount codes. I managed to get 20% off with a code I found from http://www.retailmenot.com/

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Using Apple Hardware Test on your MacBook, iMac or Mac Pro

Posted on August 27, 2010 by Clive Sweeting

Back in the good ol’ days, if you wanted to find out if you had a hardware fault with a Mac, you need to use the Apple Hardware Test CD that came with your Mac, or use the restricted Apple Service Tools. However, with more modern Intel based Macs, Apple have used some of the space in the “Firmware” Boot ROM to stick the test tool directly onto the Mac.

If you hold down F2 on startup, you may, depending on your model, be able to start the hardware tests. Typically they won’t find anything, unless you enable test looping (Apple + L) and leave it running for a few days, but it’s worth a quick look.

A customer in Bath had a problem with it intermittently failing to boot; which could point to a failing MacBook hard drive. I replaced the drive, copied their data onto the new drive and took a Time Machine backup. However I couldn’t find any evidence in the system.log of disk I/O errors, so a quick trip into the hardware tests was called for, which also revealed nothing…

Posted in Troubleshooting | Tagged , , | 1 Comment

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