To be frank, I didn't expect much from this PSU tester (PM123) the first time I took it out of its case. I considered its high price and wondered whether it is justified. After testing it thoroughly for a while, however, my opinion has changed. This PSU tester can be invaluable to anyone wanting to quickly but pretty thoroughly test a power supply without it breaking the bank or devoting countless hours to learning how to operate electronic loads, oscilloscopes, and power analyzers. The PassMark PSU tester is also portable, so you can easily carry it around in its hard case for PSU testing in the field instead of taking each PSU into your lab.

The voltage, timing, and slew rating readings are accurate enough for the size and price of this tool, and the embedded screen is a blessing since it makes this tester fully mobile and independent of a PC system. You don't have to carry a laptop with you unless you want to keep logs or connect more than a PSU tester at a time. Moreover, the software application is easy to use and puts all significant operations on the same screen without having to change tabs or open other windows. That having been said, it may be confusing for novice users as it will still take some time to get used to.

In the same vein, not everything is perfect, also since this is the first version of this PSU tester. For starters, there is no mention of how you can calibrate this tester even though calibration is essential, as all measuring equipment has to be recalibrated at regular intervals for measurements to stay accurate. Uncalibrated testing equipment becomes useless regardless of price otherwise, which is why you cannot trust results from labs that have equipment that isn't calibrated at regular intervals.

Another downside of the PM123 is that in standalone mode, its resistors get hot quickly, which has it shut down within a minute. The use of resistors with proper heat sinks would probably increase the size of the PSU tester, but it would also provide more operational time in standalone mode. Ripple measurements were also very inaccurate even though the PM123 uses the correct filtering capacitors to simulate the system's mainboard. Ripple measurements require a decent scope that can on its own easily cost as much as the PM123, which means its inaccurate ripple measurements are not surprising. That having been said, ripple filtering is an important performance factor. Ripple at 5VSB is also important as many PSUs fail to start properly because of a bad 5VSB circuit, so it would be nice to get ripple readings at 5VSB as well.

The single PCIe connector is a bummer, especially as all high-end graphics cards at least require two. The same goes for the EPS connectors—most high-end mainboards either need two EPS or an EPS along an ATX12V connector. A good idea would be for PassMark to release an enhanced version of this tester with a pair of EPS and PCIe connectors for more demanding users who wouldn't mind paying more than for the plain PSU tester. Finally, clearance around the ATX connector is not enough as it can create a problem with the ATX connectors of some PSUs. In my case, I had a problem with the Super Flower Leadex III ARGB model I used, so I had to use an ATX 24 Pin 90° adapter to connect the PSU's 24-pin ATX connector to the tester.

I liked the PM123 despite its restrictions and shortcomings, which means it has earned a place in my lab. With some upgrades, it can become an excellent tool for everyone interested in exploring the magical PSU world. It costs around as much as a higher-end graphics card, but won't lose its value over time and will help you quickly evaluate the operating state of a power supply. This is not a tool for the average user, but, rather, those wanting to learn more about PSUs, and technicians, of course, who will highly appreciate its features and capabilities. Kudos to PassMark for their good work, and I hope their engineers will hear of my suggestions to come up with something even better in the near future.