Worth it for me to "upgrade" to a lower wattage, higher efficiency PSU?

[Phantomaniac]

I built my i7 rig with a 760 watt PSU, thinking I might get another 4870 at some point. However I've realized that by the time I'd even notice a significant performance hit in newer games (running at 1680x1050), I'd most likely be better off just upgrading to a new generation single card. According to extreme PSU calculator, my system draws just over 400 watts at 90% load. This means my current PSU probably doesn't even hit 20% usage when ilding, which is where my computer spends most of its on time (web browsing, downloading, etc). Thus my PSU is highly inefficient most of the time.

Now the reason I'm so interested in efficiency is because I'm going to be moving out on my own soon, so I'll be paying for electricity. Do you guys think it'd be worth it for me to upgrade to a lower wattage, higher efficiency PSU? I had my eye on this:

http://www.newegg.com/Product/Produc...82E16817341037

What do you think: tangible savings, or not worth the cash?

 

[Meghan54]

Understand, that power supply is EOL'd.

And also, do not take what reviews you've seen for the Z-Series 850W and hope to apply them to the 550W.

The 550W Z-Series isn't the same manufacturer who makes the one reviewed at jonnyguru.com or hardwaresecrets or HardOCP.

The 550W unit is an FSP Epsilon platform, a very hit or miss platform, which even at their best, are only very good. And do not make the mistake of equating high efficiency for good build quality; there are some rather poorly built units out there that have been rated highly in efficiency.

 

[Phantomaniac]

Understand, that power supply is EOL'd.

And also, do not take what reviews you've seen for the Z-Series 850W and hope to apply them to the 550W.

The 550W Z-Series isn't the same manufacturer who makes the one reviewed at jonnyguru.com or hardwaresecrets or HardOCP.

The 550W unit is an FSP Epsilon platform, a very hit or miss platform, which even at their best, are only very good. And do not make the mistake of equating high efficiency for good build quality; there are some rather poorly built units out there that have been rated highly in efficiency.

I appriciate the input, but I was hoping for more of a general opinion of whether it would be a good idea for me to upgrade in terms of power/electricity savings. I'm not set on buying any specific PSU yet.

 

[C1]

Actually youre the only one who can answer that. In general, the engineering analysis involves the time it takes to recoup one's investment thru savings versus the expected life of the system. But this involves variables well under your control such as how continuously the system is running & under what conditions (eg, standby versus video rendering). Other factors such as effort to install & component reliability play a part.

A possibility is to install the more efficient PSU & keep the original for backup.

In general, for me, I would choose the most reliable PSU over worry about any electrical cost. What good is saving a few cents on electricity if the PSU takes out your system?

 

[Lonyo]

I would think the change would take a very long time to pay itself off unless you plan on reselling your existing PSU.

 

[Russwinters]

It will only make a marginal difference.


Keep in mind that a higher watt PSU you doesn't mean that your system is pulling more power, that is dependent on the cpu,gpu,etc.

efficiency is the key thing to look at, but really going for say a 80+ to a 85 or 90+ is only going to net you like ~$50 savings a year

 

[kalrith]

efficiency is the key thing to look at, but really going for say a 80+ to a 85 or 90+ is only going to net you like ~$50 savings a year

It's very unlikely that he'll save nearly that much by going to a higher efficiency psu. I have an HTPC that requires 40-50W DC at idle. When I first built it, I used an Ultra X-Finity 600W psu that I got FAR a few years ago. I leave it on 24/7, so I researched a ton into how much I would save in electricity (using numbers from my utility bill) by switching to a high-efficiency psu and how long it would take to recoup the up-front psu cost in energy savings.

I pulled a bunch of numbers off of SPCR for AC inpute required for 40.2W DC output and 64.3W DC output (since I'm probably somewhere between those two). The highest cost savings per year would be only $6.77, and that was from a $90 PicoPSU 120W, meaning it would take 13 years to recoup the up-front psu cost. The psu that made the most financial sense was a $30 Fortron Source 300W psu, which would save me $3.18 per year. That psu would take the least amount of time to recoup the up-front psu cost, only taking a measly 9.6 years to do so.

If you have a Kill-A-Watt, you can see what your system pulls at idle (this would be the AC input) and that would give you an idea of how much it costs to run your PC. My PC costs $32 to idle 24/7 for an entire year. Even if I found a psu with perfect efficiency, it would only save me $10 per year in electricity costs, and that psu would likely be many times more than $10.

You might find a better cost savings by using CrystalCPUID. It costs nothing but time to set it up, and you can set it to drop the cpu multiplier and voltage at idle and automatically increase those at load. One reason my HTPC idles so low is because I drop the speed to 1.2 GHz and the voltage to a ridiculously low amount (can't think of it off the top of my head). Here's the SPCR guide on how to set up CrystalCPUID.

 

[dualsmp]

Your probably very close to idling at 150w with a i7 + 4870 which is ~20% load for your PSU. Not worth upgrading.

 

[Phantomaniac]

Thanks for the input guys. I looked up detailed specs for my current PSU and it looks to be at least 80% efficient at all load levels already. Doesn't seem worth an upgrade for a few extra percentage points.

You might find a better cost savings by using CrystalCPUID. It costs nothing but time to set it up, and you can set it to drop the cpu multiplier and voltage at idle and automatically increase those at load. One reason my HTPC idles so low is because I drop the speed to 1.2 GHz and the voltage to a ridiculously low amount (can't think of it off the top of my head). Here's the SPCR guide on how to set up CrystalCPUID.

I already have Intel SpeedStep enabled, which drops the multi to 12x at idle. Can CrystalCPUID go lower?

 

[kalrith]

I already have Intel SpeedStep enabled, which drops the multi to 12x at idle. Can CrystalCPUID go lower?

It drops mine to 4x at idle, and I think it drops the vcore to .8v or .85v at idle, which is where the real power savings come from. At load it bumps the vcore to stock (1.25v) and the multiplier to 9.5x, which is stock. I've got it overclocked just a bit, so it runs at about 2.4GHz at load and 1GHz at idle.

Obviously results will vary between cpus and mobos. My gaming PC was not nearly as responsive to lowering the voltage; however, I chose the HTPC's mobo (Abit AN-M2) and cpu (BE-2300) specifically for their power savings at idle since I knew I'd have it on 24/7 for several years.

 

[jchu14]

EDIT: hah teaches me to not read the whole thread before replying. kalrith had already covered most what I've posted.

yea it will take a long time for you to recoup your money.

Let's say you got a new psu that is 90% efficient at 150watt output, that requires an input of 166 watt input. Compared to your current 80% efficent psu, which will draw 180 watt. That's a difference of 14 watt.

Assuming you run your computer 24x365, that translates to a saving of 123kwhr per year. So if you live in Idaho, where electricity costs only about 7cent/kwh, you will save $8.61 a year. If you live in the most expensive state,Hawaii, then you will save $29.50 a year.

You should do some estimations of your usage to see if upgrading it is worth it for your particular case.