Corsair TX850W (CMPSU-850TX)
This is another model from Corsair. It has the same wattage rating of 850 watts but hails from the more affordable TX series.
The packaging of this series is yellow.
Besides the color of the labels, this model is shorter than the HX850W and, which is more important, lacks detachable cables.
Despite Corsair’s having removed all markings from the chokes and transformers, I can easily tell the PSH platform from Channel Well Technology here as I have seen it in dozens of products selling under different brands. It seems to be the most popular platform for branded PSUs in the world and has been selling successfully for years, undergoing but minor revisions. Like the HX850W, this PSU has dedicated voltage regulation but the latter is based on magnetic amplifiers with chokes rather than on DC-DC converters.
KZE series electrolytic capacitors from United Chemi-Con are installed at the PSU’s output. A few solid-state capacitors have been thrown in as well.
This PSU can yield nearly all of its output power – 840 out of 850 watts – via the +12V rail which is not split into multiple output lines. The PSU is just as good as its more expensive HX series cousin in terms of load capacity. It even has more robust +5 and +3.3V rails although this is no advantage. Today’s computers just don’t load those rails much.
Cables and Connectors
The PSU is equipped with the following cables and connectors:
- Mainboard cable with a 20+4-pin connector (59 cm)
- CPU cable with a 4+4-pin connector (60 cm)
- Four graphics card cables with one 6+2-pin connector on each (60 cm)
- Two cables with four PATA power connectors and one floppy-drive plug on each (41+15+15+15+15 cm)
- Two cables with four SATA power connectors on each (41+15+15+15 cm)
The TX850W is inferior to the HX850W in this respect, having fewer cables for both graphics cards and HDDs. Anyway, it is going to be able to power most top-end gaming configurations without any adapters, too.
Working with my APC SmartUPS SC 620, this power supply was stable at loads up to 365 watts when powered by the mains and up to 330 watts when powered by the batteries. They had no problems switching to the UPS’s batteries.
Output Voltage Stability
The +12V voltage is ideal, deflecting less than 1%. The other two voltages deflect less than 3%, which is a good result, too.
Output Voltage Ripple
High-frequency pulsation can be observed on each of the three main power rails but it is far below the permissible limits.
The PSU is cooled by a 140x140x25mm fan manufactured by Onghua. I guess it’s the first time I ever hear this name. I’m not inclined to trust such obscure brands but the fan did not produce any foreign noises in my sample of the PSU. The impeller is half covered with a piece of translucent plastic film.
The fan is rotating at about 900 RPM until a load of 400 watts. Then it rapidly accelerates, reaching a peak speed of 2000 RPM. The TX850W is going to be a little quieter than the HX850W under low loads, but the latter will be much better under medium and high loads.
Efficiency and Power Factor
Although not new, the PSH platform can still deliver good results: the efficiency is 87% at the peak and easily remains above 80% in the load range of 100 watts to full load.
The standby voltage is set somewhat higher than necessary by default (within the permissible limits, though), which helps it keep above 5 volts at full load.
While the Corsair HX850W is a newest model representing a newest platform, the TX850W is yet another reincarnation of the well-known PSH platform from Channel Well. However, this PSU delivers good electrical parameters and is overall a good choice for a top-end gaming computer.
You may only want to prefer the more expensive HX series model if you need its higher efficiency and quieter operation at high loads. Besides, the HX model has more connectors and modular cables.