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ZM500-RS Resonant Switching 500W PSU
(1 review)

Zalman ZM500-RS Resonant Switching 500W PSU

The first of its kind in the PC market, Zalman's new Resonant Switching power supply offers the size, cost and efficiency characteristics of a standard switch-mode power supply, but with drastically reduced EMI (electromagnetic interference).

Brand new: Resonant Switching Circuit

We are pleased to present Zalman's new mid-range power supply which pioneers a complete circuit redesign, utilising a new "resonant switching" system which compares very favourably with standard switch-mode power supplies in several areas. Firstly, EMI (electromagnetic interference) is drastically reduced, meaning that the unit operates much more "cleanly" from an electromagnetic point of view.

In addition, unwanted heat generation is reduced by minimising "switching loss" through a technique called Zero Voltage Switching (ZVS). Furthermore, the need for an output inductor is eliminated, leading to outstanding stability and reliability and reduced electromagnetic and acoustic noise. Because less heat is produced as an effect of improved efficiency, the unit's (already very quiet) fan can run more slowly which in turn means even quieter operation.

Dual independent 12V rails and Resonant Switching circuitry6+2-pin and 6-pin PCI-E video card power connectorsATX12V (4-pin) and EPS12V (8-pin) CPU power connectorsATX20+4-pin mainboard power connectorTwin SATA power connectors
Dual independent 12V rails and Resonant Switching circuitry
6+2-pin and 6-pin PCI-E video card power connectors
ATX12V (4-pin) and EPS12V (8-pin) CPU power connectors
ATX20+4-pin mainboard power connector
Twin SATA power connectors

Safety, reliability and quietness

The ZM500-RS offers multiple safety features including over-voltage protection, over-current protection, short-circuit protection, under-voltage protection and over-temperature protection. As you would expect, it passes all internationally recognised safety approvals and electromagnetic compatibility (EMC) certifications, including UL, FCC, CE, CB and KCC.

It comes with mounting screws, cable ties and a user manual and unlike modular power supplies, all cables are permanently attached to the unit meaning you won't need to go looking for them when the time comes to upgrade and add another drive or card to your PC! It has two independent +12VDC rails, so you can be sure that any voltage ripples or current spikes caused by your graphics cards or peripherals will not appear on the supply feeding your processor and motherboard, translating into extra stability and reliability.

Unsurprisingly, the fan is a top-quality unit with hydro bearing for low noise and long life (150,000 hours expected lifespan, or if you prefer, over 17 years!). Its control circuit is linked to an internal temperature sensor, so the fan will only ever increase in speed if the unit detects that it is working hard and needs a little extra cooling. At all other times, the fan will run at a minimum nominal speed, providing you with a quiet and comfortable computing environment.


  1. Brand new Resonant Switching circuit design for high efficiency and low EMI
  2. ATX12V v2.3 compliant
  3. 87% maximum efficiency – 80 PLUS Certified
  4. Two independent +12VDC power rails
  5. Ultra-quiet 120mm fan with hydro bearings
  6. NVIDIA SLI and ATI CrossFire Ready
  7. 3 year warranty

Form factorATX12V v2.3 / EPS 12V
+3.3V max load24 A
+5V max load24 A
+12V1 max load18 A
+12V2 max load18 A
Combined maximum output +3.3V / +5V130 W
-12V max load0.5A
+5VSB maximum standby current3.0 A
PFC TypeActive PFC
Power Factor99% max
Power conversion efficiency87% max @ 230 VAC
Number of hard drive connectors4
SATA connectors2
Number of floppy drive connectors1
Dimensions, mm140(L) x 150(W) x 86(H)
ATX12V (4-pin)/EPS12V (8-pin) supportYes, splitter
20/24-pin ATX connectorYes
PCI-E supportOne 6-pin and one 8/6-pin
Mains input voltage100-240 VAC, 50-60 Hz
Fan speed controlThermal
Over voltage protectionYes
Over current protectionYes
Short circuit protectionYes
Over temperature protectionYes
Under voltage protectionYes
EMC, safety approvalsCE, CB, UL, KCC, FCC
Mains input voltage selectionAuto-range
Length of motherboard power cable45 cm (approx)
Fan speed 800 RPM - 1250 RPM depending on load
Acoustic noise level18-25 dB depending on fan speed
Warranty36 months

Customer Reviews

Really fine PSU


I'm very happy with this PSU. All the cables have been put into sheaths and tie-wrapped, making them ultra neat and less likely to be a problem within your case. The build quality is very high and the unit is super-quiet. I also thought it was a nice touch to supply this with a mains cable and extra tie-wraps and mounting screws.


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