This 750 W power supply from Coolmax can be found at Newegg.com for only USD 60, a price way below the one from good 750 W units we’ve already reviewed. Let’s see if you can save money buying this unit or if it is better to stick with a product from a different brand.
This power supply is manufactured by a company called LongYi Electronics, which is so small that they don’t even have a website.
Coolmax CUL-750B 750 W is 6 19/64” (160 mm) deep, using a 135 mm fan on its bottom (the product box says this unit uses a 140 mm fan, but this information is wrong). This unit features active PFC.
A small modular cabling system is available, with only three connectors: one red for a video card power cable and two black for peripheral and SATA power cables. Most cables are permanently attached to the power supply, and these cables use a nylon protection that comes from inside the unit. All cables use 18 AWG wires, which is the correct gauge to be used. The cables included are:
- Main motherboard cable with a 20/24-pin connector, 14 ½” (37 cm) long (permanently attached to the power supply).
- One cable with two ATX12V connectors that together form one EPS12V connector, 15 3/8” (39 cm) long (permanently attached to the power supply).
- One six/eight-pin connector for video cards, 16 1/8” (41 cm) long (permanently attached to the power supply).
- One six-pin connector for video cards, 16 1/8” (41 cm) long (modular cabling system).
- Two cables with two SATA power connectors each, 19 ¼” (49 cm) to the first connector, 5 7/8” (15 cm) between connectors (one cable permanently attached to the power supply, one cable on the modular cabling system).
- One cable with two standard peripheral power connectors, 15 ¾” (40 cm) to the first connector, 5 7/8” (15 cm) between connectors (permanently attached to the power supply).
- One cable with two standard peripheral power connectors and one floppy disk drive power connector, 15 ¾” (40 cm) to the first connector, 5 7/8” (15 cm) between connectors (modular cabling system).
This configuration is simply ridiculous for a 750 W power supply. Most cables are too short, there is only four SATA power connectors and the ATX12V/EPS12V has only two +12 V wires coming from the power supply, instead of four, which would be the correct configuration.
Now let’s take an in-depth look inside this power supply.
- 1. Introduction
- 2. A Look Inside The Coolmax CUL-750B 750 W
- 3. Transient Filtering Stage
- 4. Primary Analysis
- 5. Secondary Analysis
- 6. Power Distribution
- 7. Load Tests
- 8. The Power Supply Burning
- 9. Main Specifications
- 10. Conclusions