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Pros, Cons And Final Verdict
Although Sirfa delivers budget-friendly products that score high performance per dollar ratios, it cannot compete with vendors like Seasonic and Super Flower when it comes to absolute performance. The ZM750-EBT falls behind the competition, and the only thing saving its bacon is a low price. But spending $10 or $20 more gets you a PSU with better ripple suppression, longer hold-up time and quieter operation. It's your call whether to spend a bit extra or insist on a budget under $100.
Despite its disappointing performance, the ZM750-EBT's build quality is good, and the choice to go with Teapo capacitors seems to be a good one. While they're inferior to Japanese caps, we like them better than most Chinese capacitors and they aren't super expensive. This is why Teapo caps are favored on low-cost power supplies, and the truth is that a PSU's cap and fan choices are among the most important since they affect reliability. Speaking of, Zalman apparently trusts this platform a lot; it recently upgraded the factory warranty from five years to seven. This is a big selling point, and we're certain it'll help improve sales.
The ZM750-EBT does not match the other 750W 80 Plus Gold PSUs out there, owing to its poor ripple suppression. If Sirfa had managed to keep ripple within the ATX spec, even under tough operating conditions, then Zalman would have fared much better. Unfortunately, it seems like the company has a good reason to rate this supply at up to 40 °C for continuous full-load operation, even though the ATX spec recommends at least 50 °C.
Something else that bothered us about the ZM750-EBT is its low hold-up time, which, combined with a PWR_OK signal that drops very late, can lead to dangerous situations for your hardware. According to the ATX spec, all rails should be within the load regulation limits when the PWR_OK signal is zero, in case of AC power loss, and not the other way around. This is a great shame of course; all vendors should follow the ATX spec's requirements, especially when they claim that their products are compatible with a version of the specification.
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Aris Mpitziopoulos is a Contributing Editor for Tom's Hardware, covering Power Supplies.
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