Juan’s Gear Diary – Power Supplies


To start off my series of articles on rebuilding my desktop, I want to start with one of the most important pieces of equipment in your rig–which is often one of the most over looked:

Your power supply.

If you’re building your own system, you probably have a need not satisfied by standard “off the shelf” computers. That could be gaming, A/V editing, running a home server, or any number of other applications. A stock system can probably accomplish any of these tasks, but custom tailoring the internals of your rig will usually lead to a much nicer experience.

So if you’re going to go through the time and effort to pick out a processor, motherboard, RAM, hard drives, and video card, why would you skimp on the device that’s going to power the whole thing?

It reminds me of a friend growing up who used to “hotrod” his cars. He would spend a lot of time and money on engine mods, but rarely spent much time on brakes and suspension. He would end up with these cars that were fast, but couldn’t maneuver or stop. Scary stuff.

I kinda look at computer builds the same way; it’s got to be a total package deal if you’re expecting performance, stability, and longevity.

I usually have an idea of what kind of system I want to build, but I try to work backwards from the processor. I’ll buy everything that’s still compatible with my old system first (hard drives, video card), then move all of that over to the new system when I’m ready to buy the new proc. This means I usually end up building the system over the course of several months, and try to time the processor drop with the absolute newest processor tech available. You can’t future proof tech (as soon as you buy anything, it’s surpassed in a matter of weeks…sometimes days), but this build schedule gives me the most longevity I can hope for.

My current system was doing well with my old power supply, but upgrading the video card meant stepping up my game. My old Nvidia 6600 wasn’t really taxing my 500 watt PSU. Unfortunately that PSU couldn’t handle my new GTX 560 Ti. Not only was total output too low for this new card, it didn’t even have the right connectors to hook up and power the card.

NZXT was kind enough to send over a 750 watt 80+ Gold certified PSU. Their power unit also features an oversized cooling fan, modular cables, and it’s designed to fit into their line of enthusiast cases (which we’ll be talking about in my next article).

The PSU market has been undergoing something of a transformation lately. As equipment gets more powerful, demanding more energy, and creating more waste/heat, a greater focus has been placed on efficiency. The 80 + badge was created to easily show customers devices that provide greater than 80% efficiency when under load.   In the past, PSU’s typically ran anywhere between 50% and 80% depending on the quality of manufacturing, but the industry was very inconsistent in communicating to consumers how efficient their gear was.

This can have a noticeable impact on your energy consumption. This efficiency is calculated by measuring how much power is drawn from the outlet, then dividing that amount by how much power the PSU is able to output.

Take an extreme example of a horrible low end PSU. Let’s say you have a gut-rot 500 watt PSU that’s only 50% efficient at load. To generate that 500 watts for your system, the PSU has to pull in 1000 watts of power from the wall. 500 watts will be delivered to your system internals and 500 watts of power will be wasted as heat. Heat kills electronics, so you’ll have to deal with that heat belching into your case.

That is of course an extreme example, and you’d really have to low-ball your PSU to find one that performs that poorly; but nowadays there’s really good information available to find PSU’s that perform on the opposite end of the efficiency spectrum.

The 80+ badge also comes with different “grades” of efficiency. My new NZXT is 80+ Gold, which means it reaches almost 90% efficiency at full load.

You’ll want to be careful to not over buy on your PSU. PSU’s are most efficient when being run between half and three quarters of full load. There’s little reason to buy a 1000 watt supply if you’re not going to max out the gear in your case. You’ll want to read up on both the idle draw and full load draw of the gear you’ll be buying, making sure that at idle your system isn’t drawing too little power from your PSU, but at full load your PSU can keep up with everything in the case.

For example, my GTX 560 will draw 160 watts of power idling, doing nothing but showing me my desktop, but at full load (like when I’m playing Crysis) that card will pull over 300 watts of power all by itself. I also need to feed a quad core processor, RAM, multiple hard drives, disk drive, and motherboard. It’s a little bit of a balancing act making sure you’re pairing the right PSU to the gear you want to run.

I find this is one way that commodity manufacturers are able to bring out desktop computers so inexpensively. They’ll often put in the bare minimum PSU that can power everything in the case. This means though, that at load that little PSU is running fully loaded, which isn’t an efficient way to run. It’s costing you money on your energy bills, and cooking the inside of your system with extra heat. That “inexpensive” desktop isn’t really so inexpensive in the long run…

I was really happy to see NZXT use a larger fan than standard. Fan size is critically important if you value having a cool and quiet system. The larger the fan, the more air it can push out of your case at a slower speed. The slower your fan spins, the quieter it is. Smaller fans also make a higher pitched sound.

Back in the day, 80mm was a pretty standard fan size, and those things would buzz like large angry hornets. My 500 watt PSU had a 120mm which had a MUCH more pleasant sound to it. My new NZXT has a 140mm fan built into it, which is nearly silent. The sound you can hear off of it is also pleasantly low pitched, sort of an easy yawn compared to the whiny buzz of the old days.

Having a fan that large though means this PSU wont fit in all cases. It’s just a little too large for my old standard ATX desktop case, so it really is designed to be used with an enthusiast/gamer/pro workstation/server case. That was a really complicated way of saying “you’ll need a BIG case”…

The modular cable design of this PSU is a revelation. I’ll never use a non-modular design ever again. Older PSU’s would hardwire all the cables into the supply. If you weren’t using all of those cables, they’d still be in your case blocking air flow. It’s why old PC’s are usually described as being “rats nests”. A modular design means you only plug in the cables you need. It keeps your case a lot cleaner.

I bet you thought you’d never see a 1300 word article about power supplies. I mean, that’s longer than the wiki! Hopefully you’ve learned a little, and for those of you interested in building, maintaining, and upgrading your own systems you’ll be able to eke out better performance, more efficiency, cooler temps, and lower energy bills with your next PSU purchase.

In all, I’m VERY happy with my new PSU, and I can’t thank NZXT enough for sending it my way.

Next time we’ll take a look at cases. Cuz what’s the fun of having this awesome PSU if it wont fit in my little case…