07-26-2017 09:53 AM
A reviewer for one of the adapters available on Amazon says the following:
"It marginally does the job. Allow me to explain the predicament.
1) Lenovo's PSU is good for 250 Watts, which will adequately support i7 CPU, added memory and extra HDD. All peripherals on this computer system use the power provided by the motherboard, as it will turn these peripherals off on power-down.
2) Power to the motherboard is provided by five 12V wires/contacts from the PSU. Each contact and wire has a safe rating of 6.0 amps or a total maximum of 360 Watts of continuous power.
3) Cable provided for this adapter uses only four of the possible five contacts (go ahead and count them). Consequently the derated power that can be continuously delivered is now only 288 Watts.
4) Most PSUs require a 5VDC load for the PSU to operate. Lenovo motherboard uses only 12VDC.
The 4 points made above are facts and cannot be disputed.
Most other PSUs have a constantly on housekeeping VBUS (5VDC) used for deep sleep wake-up. Lenovo PSU is left completely on, as it does not have a separate 5VDC (VBUS) for power on. This is clearly stated in the product description for this adapter cable, so whining about it, only proves that the person neglected to read it.
Lenovo could have done a better job designing this power system. They could have used a single 12V system, this would have been great, but in hindsight had to include a minus 12V rail on their motherboards, as they obviously forgot to include one on the motherboard. Furthermore, they could have added another 12V contact to the PSU input on the motherboard, allowing for greater margins for display adapters and peripherals.
I gave this product a 3 based upon points 3 and 4. If your PSU failed and needed a replacement, this product is useful. If you plan on adding a graphic card that uses an external power connection, this product is useful. Beware that many PSUs require a 5VDC load. typically this means adding a 10 ohm, 5 watt resistor across 5VDC and ground.
I purchased this cable, but decided to remove the contacts from a standard PSU and connect them to a 10 pin connector. I added a third 12V wire and contact so that I would have the maximum power to the motherboard. This is time consuming and the return is a 15% yield in power gain. Your mileage will vary."
Can anyone confirm?