What kind of efficiency rating does this power supply have, and how does it perform under full load?

The power supply has up to 90% conversion efficiency, which indicates high efficiency and energy saving performance under full load.

Is this power supply compatible with all types of GPUs, or are there specific models it supports?

This power supply supports up to 6/8 GPUs, but specific models are not mentioned in the product information.

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1600W 1800W 2000W Mining Power Supply Modular Mining PC Power PSU Supports 6/8 GPU Rig for ETH Bitcoin Ethereum Miner (Multiple 1600W PSU for 6GPU)

This mining power supply can be a perfect tool for your ETH Coin rig. DC circuit design, stable voltage output. Interface: 1600W20+4p, 3IDE, 6SATA,12*6+2p. 1800W20+4p, 3IDE, 8SATA,16*6+2p. 2000W20+4p, 3IDE, 8SATA,16*6+2p.
This mining power supply is better for Bitcoin GPU mining, 160V-270V Power Supply Mining Machine. 100% Brand New and High quality-GPU: Support Up to 6/8 GPU(GPU is not included); Fit for Miner and other Server.
140mm large fan design for optimal system cooling and maximizing performance.Compatible with quality, efficiency and stability balance, pursuing continuous real power output.
The power supply rated output power 1600W/1800W/2000W, With up to 90% conversion efficiency, high efficiency and energy saving, Using a new large-capacity large magnetic ring material, the performance is very stable, Widely used in variety of mines and industrial equipment.
This power supply is special for mining machine, in order to effectively dissipate heat, the fan speed is