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Practical Electronics Editorial offices Electron Publishing Tel +61 2 9939 3295 (Australia) Email pe<at>pemag.au Web www.electronpublishing.com Address mail to: Electron Publishing (Australia) PO Box 194, Matraville NSW 2036 Australia Advertising enquiries +61 2 9939 3295 pe<at>pemag.au Editor Nicholas Vinen Publisher Nicholas Vinen Digital subscriptions Stewart Kearn Tel 07918 614662 Online Editor Alan Winstanley Web Systems Kris Thain Production Bao Smith Technical staff Tim Blythman, John Clarke Print subscriptions Practical Electronics Subscriptions PO Box 6337 Bournemouth BH1 9EH Tel 01202 087631 United Kingdom Email pesubs<at>selectps.com Technical enquiries We regret that technical enquiries cannot be answered over the telephone. We are unable to offer any advice on the use, purchase, repair or modification of commercial equipment or the incorporation or modification of designs published in the magazine. Questions about articles or projects should be sent to the editor by email: pe<at>pemag.au Projects and circuits All reasonable precautions are taken to ensure that the advice and data given to readers is reliable. We cannot, however, guarantee it and we cannot accept legal responsibility for it. Some projects and circuits published in Practical Electronics employ voltages that can be lethal. Do not build, test, modify or fix any mains-powered equipment unless you fully understand the safety aspects involved and you use an RCD (GFCI) adaptor. Component supplies Silicon Chip Publications may offer kits or other parts for making our projects, but not in all cases. When kits are not available, readers will need to find and source parts themselves. We advise readers to check that all parts are still available before commencing any project in a back-dated issue. 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The laws vary from country to country; readers should check local laws. 2 Volume 54. No. 11 November 2025 ISSN 2632 573X Editorial Many SSDs have a limited lifespan no matter what There’s a myth that’s been floating around for a while: solid-state drives (SSDs) are more reliable than mechanical hard drives because they don’t have moving parts. At first glance, it makes sense. Things that spin or slide will wear and eventually fail. But “no moving parts” doesn’t mean “lasts forever”. Mechanical hard drives are, in many ways, miracles of engineering. They spin at 7200 RPM day and night for years on end, with the heads flying just above the surface of the platters while they read and write data. In my experience, if you keep them cool and don’t knock them about, they often last decades. Sure, one fails every now and then, but it’s rarer than many people think. In contrast, I’ve had much worse luck with SSDs. They start out wonderfully fast – handling gigabytes per second when new – but over time, their performance can fall away. Sometimes, they simply fail without warning, which has happened to me a couple of times. A few years ago, we replaced some trusty old mechanical drives with three Western Digital Green SSDs in a RAID5 array. These held our magazine layouts, product photos and other day-to-day files. For the first few years, everything seemed fine. Then I noticed that instead of handling the hundreds of megabytes per second you’d expect, the throughput had collapsed to less than 10MB/s. That’s worse than an old mechanical drive from the 1990s! Testing each SSD individually showed the same thing. I replaced them with newer, higher-end SSDs and performance immediately returned to normal. The old ones, meanwhile, were too slow even for backups. I gave up after trying to copy a few hundred gigabytes; two days later it was still crawling along, barely 20% done. After only 4½ years of light use, all three SSDs were basically unusable. Why does this happen? NAND flash has a limited number of write/ erase cycles, typically a few thousand for consumer-grade TLC or QLC flash. Controllers use wear-levelling to spread the writes evenly, but the cheaper the drive, the less margin you have before cells wear out. Once that happens, performance falls off a cliff. And unlike hard drives, which often give some warning as bad sectors multiply or the bearings get noisy, SSDs can just stop dead. So while it’s tempting to think that “solid state” means “permanent”, the reality is different. SSDs are quieter, cooler and much faster than mechanical drives, but they’re not invincible. Don’t assume an SSD will last forever. Buy good ones and always keep backups. Spinning or not, no storage medium lasts forever. Nicholas Vinen, Electron Publishing (Australia)* Publisher & Editor, Practical Electronics Magazine * a division of Silicon Chip Publications Pty Ltd. Practical Electronics | November | 2025