Corsair VX450W

[W1zzard]

To read this review go to: http://www.techpowerup.com/reviews/Corsair/VX_450W/

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[WarEagleAU]

Great price for a PSU that could prolly handle 600w totals. Thanks W1zz.

[hat]

Got it now, it's great.

[ghost101]

Yep, great PSU.
The 550w version i have has even better efficiency with the same noise. It has 2 pci-e conncetors and being £10 cheaper than a hx520 i really dont understand why people dont go for it more.

[hat]

modular, dual 12v rails

[btarunr]

That's the best 450W PSU I've seen in a long time....the efficiency is totally off the charts. This PSU easily out-does several cheap 600W PSUs.

Awesome review, W1z!

[ghost101]

Originally Posted by hat

modular, dual 12v rails

http://www.xbitlabs.com/articles/oth...su5.html#sect1

Multiple rails has always been a marketing gimmick. Heres a section from an xbitlab review. Xbitlab are probably the best and most comprehensive reviewers of PSUs.

Originally Posted by xbitlabs

Dual +12V output circuits
In good old times PC power supplies used to have one power rail for each of the output voltages (+5V, +12V, +3.3V, and a couple of negative voltages), and the maximum output power on each of the rails was not higher than 150-200W. It’s only in some high-wattage server-oriented power supplies that the load on the +5V rail could be as high as 50A, i.e. 250W. This situation was changing as computers required ever more power and the distribution of power consumption among the different power rails was shifting towards +12V.

The ATX12V 1.3 standard recommends a max current of 18A for the +12V rail and this is where a problem occurred. It was about safety regulations rather than about increasing the current load further. According to the EN-60950 standard, the maximum output power on user-accessible connectors must not exceed 240VA. It is thought that higher output power may with a higher probability lead to various disasters like inflammation in case of a short circuit or hardware failure. Obviously, this output power is achieved on the +12V rail at a current of 20A while the PSU connectors are surely user-accessible.

So, when it became necessary to push the allowable current bar higher on the +12V rail, Intel Corporation, the developer of the ATX12V standard, decided to divide that power rail into multiple ones, with a current of 18A on each, the 2A difference being left as a small reserve. Purely out of safety considerations, there was no other reason for that solution. It means that the power supply does not necessarily have to have more than one +12V power rail. It is only required that an attempt to put a load higher than 18A on any of its 12V connectors would trigger off the overcurrent protection. That’s all. This simplest way to implement this is to install a few shunts into the PSU, each of which is responsible for a group of connectors. If there’s a current of over 18A on a shunt, the protection wakes up. As a result, the output power of none of the 12V connectors can exceed 18A*12V=216VA, but the combined power on the different 12V connectors can be higher than that number.

That’s why there are virtually no power supplies existing with two, three or four +12V power rails. Why should the engineer pack additional components into the already overcrowded PSU case when he can do with just a couple of shunts and a simple chip that will be controlling the voltage in them (the resistance of a shunt being a known value, the current passing through the shunt can be known if you know the voltage).

But the marketing folk just couldn’t pass by such an opportunity and now you can read on any PSU box that dual +12V output circuits help increase power and stability, the more so if there are not two but three such lines!

You think they stopped at that? Not at all. The latest trend is power supplies that have and don’t have the splitting of the +12V rail at the same time. How? It’s simple. If the current on any of the +12V output lines exceeds the 18A threshold, the overcurrent protection becomes disabled. As a result, they can still embellish the box with the magical text, “Triple 12V Rails for Unprecedented Power and Stability”, but can also add there some nonsense that the three rails are united into one when necessary. I call this nonsense because, as I have written above, there have never been separate +12V power rails. It’s impossible to comprehend the depth of that “new technology” from a technical standpoint. In fact, they try to present the lack of one technology as another technology.

An easy way to tell when there arent actually independent 12v rails is where if you add up the amperage of the 12v rails and then multiply it by 12, it doesnt add up to the stated combined power output of the rails.

If we take the corsair 520w for example



IOf we add up the 12v rail, we get 54A. Yet the combined power output of the 12v rails is 480w. This means the combined amperage can only be 480/12 = 40A. If these were truly 2 independent rails this would not happen.

[Xolair]

Yeah, I have this PSU and it's great. Could have a bit more power, but meh, I bet it's still enough for my current card.

[btarunr]

I bought it for my brother's machine. Woot: 5 yrs warranty + authorised service-center in my city.