The least impressive computer I've used—Slow F iMac
The least impressive computer I've used—Slow F iMac
Hello, I'm a computer science student, and my troubles started when a friend shared that he had an old iMac (iMac 21.5, mid-2010) that wouldn’t power on. As someone studying this topic, I figured I could help. To be clear, this was my first real attempt at fixing a Mac—I used one for about a month at work, but switched to a Windows machine because I prefer it better. When I plugged it in at home, the computer turned on but displayed nothing. My friend took it to a repair shop, who said it was a hard drive issue and warned it would be expensive.
I tried opening Recovery (Command+R), but it wouldn’t launch, suggesting a corruption. I then removed the hard drive for testing. The technician confirmed the drive was dead, so I swapped it in with an SSD. Using a High Sierra installer (the last supported OS for this model), I installed the system. Initially, I thought it was simple—this was almost a month ago, and I’m still dealing with the same F iMac.
Everything seemed fine at launch, but testing revealed extreme slowness. Temperatures looked high, so I suspected thermal problems. After cleaning, reapplying thermal paste, and removing dust from fans, performance improved only marginally. Eventually, I booted into macOS again, which felt normal, yet the system remained unresponsive.
I checked temperatures—still elevated—and suspected a hardware fault. Cleaning everything thoroughly, updating the thermal paste, and reseating the fans didn’t help. The machine ran slowly, had no CPU activity, RAM was fine, and after an upgrade to SSD, it was still unusable.
Eventually, I tried Ubuntu on an Ubuntu USB drive. The installation went through, but when I booted into Ubuntu, the screen went black instantly, the display backlight failed, and everything froze. I attempted to switch to Windows 10, but the same issues persisted.
After some research, I discovered a driver problem with the dedicated AMD GPU. I reinstalled macOS, thinking it would fix things, but even then, the Mac remained unresponsive. I tried using Bootcamp to install drivers, but faced network errors during downloads. The screen was black, and the process kept failing.
I explored other fixes—modifying Bootcamp, creating a custom partition—but nothing resolved the core issue. Eventually, I returned to macOS, which was still extremely slow. I couldn’t find any guidance online, and the situation felt like a frustrating loop.
My friend’s PC had become a frustrating obstacle; it felt like I was constantly chasing a solution that seemed to vanish with each attempt. I’m exhausted from trying everything, and honestly, I worry about giving my friend his device back in a usable state. It’s made me feel like an inadequate technician. Lately, I’ve seen better results with older Intel machines, which run smoothly compared to this iMac.
Please help—this is really challenging.
Install LION via USB stick while pressing the designated key during startup