A 400 watt power supply puts you in the range which is suitable for a video card. Although a smaller power supply might do at time, a 400 watt power supply is enough to give the power a single modern graphics card might need to run.

Not only do these bigger power supplies allow for more power they also start to become noticeably more expensive and come with other features as switching and variable fan speeds. As there is not much to attract people to one 400 watt power supply or another, manufacturers add other features like auto shutoff to prevent damage to systems or the afore mentioned fans.

A 400 watt power supply would certainly be the better bet for not just more power but possibly smoother power, although that depends on the particular 400 watt power supply you’re looking at.

Lets examine a few 400 watt power supply units.

Coolmax Silver 400 watt power supply

Coolmax 400 watt power supply

The Coolmax comes recommended by those who have used it in the past. It is dead on as a 400 watt power supply. It comes with 6 4-pin connectors, which are the standard kind used on most CD and DVD drives as well as hard disks. There are also SATA connections and 2 floppy drive connectors. This 400 watt power supply, like most in this range has an extra little 4-pin connector so it can be adapted from a 20-pin to 24-pin motherboard connector.

As a 400 watt power supply it has an adjustable fan. It comes with 3 manually adjusted settings. The lowest should do for most day to day use and is also the quietest. The fastest setting on this 400 watt power supply is still not too loud and provides that extra cooling for when you are putting heavy loads on it.

Kingwin Alpha power 450 Watt Power Supply with 120mm fan

Kingwin 450 watt power supply

The kingwin is a well priced contendor in the 400 watt power supply category. It cost a little more than the Coolmax looked at before, but comes in a lot cheaper than many of the other 400 watt power supply units.

It has a set of features fairly standard to this group. It has a 120mm fan, it can support 20 or 24 pin motherboard connector. It also has protection switches to protect it like overload protection, short circuit protection and voltage protection. One of the main features that sets this 400 watt power supply apart from the cheaper Coolmax is the auto fan-speed sensor. Instead of the speed of the fan being manually adjusted it will adjust itself according to the loads being place on it.

As a 400 watt power supply it comes in well when comparing price and cost.

Thermaltake TR2 420 watt ATX 2.0 Power Supply

Thermaltake 420 watt power supply

One thing that although not completely necessary for a power supply, but is a good indication of quality is the ATX standard. By complying with the standard, a 400 watt power supply, or any for that matter is claiming to meet the ATX standards. The standards they have to meet are not particularly stringent, but do provide a certain peace of mind about what the supply might possibly do to your computer.

Well the 400 watt power supply from Thermaltake meets the ATX 2.0 standard and delivers in performance. It performs well and to the standards it claims. The large fan keeps this power supply in the right noise range for a 400 watt power supply. The power is within range and doesn’t fluctuate too much out of the accepted 5% up or down.

Masscool 460 watt PCIe ready Power Supply

Masscool 460 watt power supply

The Masscool is a little more unknown entity in the power supply market. It’s not unkown, but there are not too many online reviews on it either.

One of the best ways to assess the quality of a power supply is with real world tests done by website. These are often just ordinary people who do this kind of thing for enjoyment, so they can give you a very honest opinion on a 400 watt power supply.

This 400 watt power supply comes with the usual compliment of power cables and does and provides all the connections that you could need from, or could be provided by a 400 watt power supply.

It does need to be noted that the Masscool was the most expensive of those looked at in the range of 400 watt power supply units.

Vantec ION2 460 watt SATA-ready power supply

Vantec 460 watt power supply

The Vantec 400 watt power supply units case is perforated with holes at the back and the front to allow the maximum flow of air into and out of the power supply. There is a large 120mm fan at the top to provide air flow to aid in the cooling.

400 watt power supply units don’t tend to get too hot, but it is worthwhile making sure that nothing goes awry by having the fans anyway. Most power supplies are not efficient enough to do without the fan to displace that extra heat.

There is the usual protection from power disruptions from this 400 watt power supply. There are SATA cables for those who have moved on to newer, faster hard drives. It will support the 24 pin power connection, and there is an adapter just in case.

The cables are sleeved, which is not a hard thing to add, but makes the difference to the feel when wiring inside your case. A 400 watt power supply needs to provide a little something extra to make it stand out.

Enermax 420 watt Dual 80mm fan power supply

Enermax Noisetaker 420 watt power supply

The Enermax is one of the better know names around, this 400 watt power supply takes the initiative to combat extra heat from the PSU. The two fans continue to run for at least two minutes after system shutdown to assure it cools down, they run for longer if they need to. The fans also have automatic speed adjustment from heat sensors in the 400 watt power supply.

There are cables for running a PCIe video card, SATA drives and all the usual cables for optical drives and hard disks.

There are two seperate 12V power rails to provide power to the CPU and the motherboard. The method of using two fans is actually suggested by AMD to provide the best cooling effect for the drive, many opt for one large 120mm fan which also reduces noise.