How much energy savings between 80Plus Gold Cert. vs. 80Plus Silver Certified?

[soarwitheagles]

Hi all!

I recently purchased a number of XFX PSU units.  Jonnyguru gave exceptional reviews on the 850 watt version:

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story5&reid=165

I installed this new XFX 850 watt in my new Intel i5-2500k/Gigabyte GA-P67A-UD3-B3.  I am very happy with it.

BUT, I just read an article where a builder is saying his SeaSonic X Series X650 80 PLUS GOLD Certified Modular Active PFC Power Supply saves him 15% power costs compared to other PSU's.

Here is my question: How much energy savings between 80Plus Gold Certified vs. 80Plus Silver Certified?  Would I really see a 15% difference in power consumption between these two units?

Any expert "Double E" guru's that can help me make an educated decision on this please?

I would appreciate any and all accurate advice.

Thanks,

Soar

[soarwitheagles]

I just found a Certification Table but I am still not sure exactly how much energy is saved from let's say a Bronze vs. a Platinium.

Is it as simple as seeing a mere 2% savings when comparing a Silver Certified PSU to a Gold Certified PSU?

If this is truly the case, then I see very little merit or incentive to upgrade from a Silver to a Gold certified PSU.

Can anyone here help me out on this?  Am I seeing this clearly?

Soar

[Dark Mantis]

Hi Soar,

Yes that is about what I wopuld have expected. The power supplies today are very eco friendly anyway and there is not going to be a massive difference between the top and bottom rated ones. Bear in mind too that most people use approximately 50% - 60% of the output which is usually the most economical level.

I certainly wouldn't swap the Silver for a Gold version. It just wouldn't make sense.

[Wonderwrench]

Hi Soar,

Yes that is about what I wopuld have expected. The power supplies today are very eco friendly anyway and there is not going to be a massive difference between the top and bottom rated ones. Bear in mind too that most people use approximately 50% - 60% of the output which is usually the most economical level.

I certainly wouldn't swap the Silver for a Gold version. It just wouldn't make sense.

"Most people use approximately 50% - 60% of the output which is usually the most economical level" You must be talking max load. Seems people my self included oversize PSU's like a SOB. Take the rig in my sig. Running OCCT PSU test cranked to the max my system draws about 465 watts from the wall.  At 90% efficiency that would make the PSU output about 420 watts.  So worst case my PSU is loaded 55%. Games I play, Crysis(1,WH,2), Dirt 2,  Stalker etc. never come close to using 420 watts. Cruising the net, email etc. my system draws about 135 watts at the wall. Guessing 85% efficiency the PSU is putting out about 115 watts. So about 15% PSU load.  So what I'm trying to get at is. People that care about efficiency should not use a PSU that is over sized. Your never going to see the efficiency the PSU is capable of if the idle load is below 20% as most PC's spend most of their time at or near idle.

soarwitheagles, I did some testing when I switch PSU's back a few months ago and these were the results.

OCZ 700GXSSLI  PSU claimed to be 80% efficent @ 115V (Typical load)
PC off 4 watts
PC on idling on desktop 132 watts
Running OCCT PSU test with default settings 445-455 watts

Corsair AX750 PSU 80 Plus Gold certified, claimed to be 90% plus efficent at 50% load
PC off 2 watts
PC on idling on desktop 123 watts
Running OCCT PSU test with default settings 395-405 watts

Wattage measured using a Kill A Watt meter.

I would say you would never see a savings going from a silver to gold PSU of the same size. If you are running a oversized PSU now switching to a smaller PSU would make way more difference.

Bill

[Dark Mantis]

Hi Bill,

Yes I would agree in principle with what you said and I was talking about max load so you were right there. Personally I like to have a bit of headroom so I am not concerned about my PSU having the power to run anything I chuck in there.

[soarwitheagles]

Hi Soar,

Yes that is about what I wopuld have expected. The power supplies today are very eco friendly anyway and there is not going to be a massive difference between the top and bottom rated ones. Bear in mind too that most people use approximately 50% - 60% of the output which is usually the most economical level.

I certainly wouldn't swap the Silver for a Gold version. It just wouldn't make sense.

"Most people use approximately 50% - 60% of the output which is usually the most economical level" You must be talking max load. Seems people my self included oversize PSU's like a SOB. Take the rig in my sig. Running OCCT PSU test cranked to the max my system draws about 465 watts from the wall.  At 90% efficiency that would make the PSU output about 420 watts.  So worst case my PSU is loaded 55%. Games I play, Crysis(1,WH,2), Dirt 2,  Stalker etc. never come close to using 420 watts. Cruising the net, email etc. my system draws about 135 watts at the wall. Guessing 85% efficiency the PSU is putting out about 115 watts. So about 15% PSU load.  So what I'm trying to get at is. People that care about efficiency should not use a PSU that is over sized. Your never going to see the efficiency the PSU is capable of if the idle load is below 20% as most PC's spend most of their time at or near idle.

soarwitheagles, I did some testing when I switch PSU's back a few months ago and these were the results.

OCZ 700GXSSLI  PSU claimed to be 80% efficent @ 115V (Typical load)
PC off 4 watts
PC on idling on desktop 132 watts
Running OCCT PSU test with default settings 445-455 watts

Corsair AX750 PSU 80 Plus Gold certified, claimed to be 90% plus efficent at 50% load
PC off 2 watts
PC on idling on desktop 123 watts
Running OCCT PSU test with default settings 395-405 watts

Wattage measured using a Kill A Watt meter.

I would say you would never see a savings going from a silver to gold PSU of the same size. If you are running a oversized PSU now switching to a smaller PSU would make way more difference.

Bill

Bill,

Your benchmarks as well as some of your statements are eye openers for me!  Thanks for posting here.

After reading your statements, I think I have been very ignorant or misinformed, or both!

I always assumed that no matter how big or small my PSU is, it would only expend the amount of power the system pulls from it!

I thought my Intel 2500k/Gigabyte GA-P67A-UD3-B3 rig would pull the same amount of watts/amps regardless of the wattage rating of my PSU...

In all reality, I only a need 500-600 watt PSU to run my rig.  I purchased the XFX 850 80Plus Silver Certified PSU thinking I would save more costs simply because the efficiency rating is higher than some of the bronze rated 500 watt PSU's.

Bill, am I correct in hearing you say that the wattage rating is also a determining factor in how much wattage my system draws?

How much would I save if I "downgraded" from the XFX 850 Silver to the Seasonic 650 Gold?

Please elaborate if you will.

Thanks,

Soar

[Wonderwrench]

Hi Soar,

Yes that is about what I wopuld have expected. The power supplies today are very eco friendly anyway and there is not going to be a massive difference between the top and bottom rated ones. Bear in mind too that most people use approximately 50% - 60% of the output which is usually the most economical level.

I certainly wouldn't swap the Silver for a Gold version. It just wouldn't make sense.

"Most people use approximately 50% - 60% of the output which is usually the most economical level" You must be talking max load. Seems people my self included oversize PSU's like a SOB. Take the rig in my sig. Running OCCT PSU test cranked to the max my system draws about 465 watts from the wall.  At 90% efficiency that would make the PSU output about 420 watts.  So worst case my PSU is loaded 55%. Games I play, Crysis(1,WH,2), Dirt 2,  Stalker etc. never come close to using 420 watts. Cruising the net, email etc. my system draws about 135 watts at the wall. Guessing 85% efficiency the PSU is putting out about 115 watts. So about 15% PSU load.  So what I'm trying to get at is. People that care about efficiency should not use a PSU that is over sized. Your never going to see the efficiency the PSU is capable of if the idle load is below 20% as most PC's spend most of their time at or near idle.

soarwitheagles, I did some testing when I switch PSU's back a few months ago and these were the results.

OCZ 700GXSSLI  PSU claimed to be 80% efficent @ 115V (Typical load)
PC off 4 watts
PC on idling on desktop 132 watts
Running OCCT PSU test with default settings 445-455 watts

Corsair AX750 PSU 80 Plus Gold certified, claimed to be 90% plus efficent at 50% load
PC off 2 watts
PC on idling on desktop 123 watts
Running OCCT PSU test with default settings 395-405 watts

Wattage measured using a Kill A Watt meter.

I would say you would never see a savings going from a silver to gold PSU of the same size. If you are running a oversized PSU now switching to a smaller PSU would make way more difference.

Bill

Bill,

Your benchmarks as well as some of your statements are eye openers for me!  Thanks for posting here.

After reading your statements, I think I have been very ignorant or misinformed, or both!

I always assumed that no matter how big or small my PSU is, it would only expend the amount of power the system pulls from it!

I thought my Intel 2500k/Gigabyte GA-P67A-UD3-B3 rig would pull the same amount of watts/amps regardless of the wattage rating of my PSU...

In all reality, I only a need 500-600 watt PSU to run my rig.  I purchased the XFX 850 80Plus Silver Certified PSU thinking I would save more costs simply because the efficiency rating is higher than some of the bronze rated 500 watt PSU's.

Bill, am I correct in hearing you say that the wattage rating is also a determining factor in how much wattage my system draws?

How much would I save if I "downgraded" from the XFX 850 Silver to the Seasonic 650 Gold?

Please elaborate if you will.

Thanks,

Soar

To really know for sure you would need to measure the wattage draw from the wall when your system is idle. We also need to know how efficient your existing PSU is at low load so we can figure its true output at idle. The trouble is I do not think anyone tests PSU's at such low load. I looked at XFX and found nothing. I also searched the net and found nothing. I think the best we can do is a wild guess. Not knowing your exact system config I would guess your PC uses less power at idle than mine does because of the 2500k you are using. So lets say your PC draws 115 watts from the wall at idle. Since your PSU is 100 watts bigger than mine and your sytem draws less. Lets say your 850 is only 75% efficient at this load. True wattage output would be 86 watts. So your PSU is barely over 10% loaded at idle. Now take a 550 watt gold PSU and lets see what happens. Even using a 550 we will be below 20% load at idle but much closer than before. Lets say the 550 is 87% efficient when your PC is idle. There is a 12% gain going to a 550 watt PSU. 12% of 86 is about 10.3 so you would save about 10 watts if I figure correctly. I would say this would be best case savings. It could be less. IMO not worth the expense of changing PSU's as it would never pay for itself unless the PC was on 24/7 and you have very high rates on electricity.

Bill

[soarwitheagles]

Thanks again Bill for sharing your thoughts and insights.  I do have two of the Kill-O-Watt meters.  I only used them one time and then left them on the shelf.  I could plug my rig into the Kill-O-Watt meter and check for wattage usage in idle and while surfing the net [I no longer play games].  Would this help me understand how much juice my rig is slurping as well as help me do a comparative study on various PSU's and rigs?

If yes, must I wait an hour or more or can I find the correct readings immediately?

Please let me know.

Thank you,

Soar

PS Also, a question for DM and Absic:  Which of my two rigs are slurping the most energy, the AMD hex core or the new Intel 2500k?

[Wonderwrench]

Thanks again Bill for sharing your thoughts and insights.  I do have two of the Kill-O-Watt meters.  I only used them one time and then left them on the shelf.  I could plug my rig into the Kill-O-Watt meter and check for wattage usage in idle and while surfing the net [I no longer play games].  Would this help me understand how much juice my rig is slurping as well as help me do a comparative study on various PSU's and rigs?

If yes, must I wait an hour or more or can I find the correct readings immediately?

Please let me know.

Thank you,

Soar

PS Also, a question for DM and Absic:  Which of my two rigs are slurping the most energy, the AMD hex core or the new Intel 2500k?

Sure a  Kill-O-Watt meter will give you the needed wattage draw from the wall almost immediately. We will still be missing accurate info in how efficient PSU's are below 20% load. I now for a fact the efficiency will drop off the farther you go below 20% but that varies from PSU model to model.

Your Kill-O-Watt meter will easily tell you which system is the most efficient. I would guess the AMD rig draws more power.

[soarwitheagles]

Thanks again Bill!

Ok, just measured my AMD rig and it is drawing 123 watts at idle, 150 watts when I surf the internet, and 200 watts when I watch a movie.

I am not sure what software to use to test full load.  I am not comfortable downloading OCCT PSU test software because it comes out of Russia.

Are there any other software programs I might use to test at full load?

I never realized the number of watts can fluctuate so widely as I do different tasks on the rig.  Very interesting!

Do you know what is really funny?  I have two brand new Galaxy GTX 480 1.5 MB Super Overclocked GPU's and each one idles at 222 watts, and suck 425 watts at load.  When I read that I decided to not use them!  I'd have to work overtime just to pay my electrical bill!

It would be nice to discover how many watts my GTX 460 is gobbling up!

Well, I am done with measuring the AMD rig for now.  I'll measure the Intel rig later.

Thanks again!

Soar

[Dark Mantis]

Hi Soar,

Regarding your question about the AMD v Intel power usage as you ahve already mentioned yourself it mostly depends on other pasrts of the system like the GPUs that you have installed more so than the CPU/motherboard. On a basic rig though I would say the Intel would be slightly ahead of the AMD at rest or just minimal use. I will be interested in your findings though.

[soarwitheagles]

Hi Soar,

Regarding your question about the AMD v Intel power usage as you ahve already mentioned yourself it mostly depends on other pasrts of the system like the GPUs that you have installed more so than the CPU/motherboard. On a basic rig though I would say the Intel would be slightly ahead of the AMD at rest or just minimal use. I will be interested in your findings though.

Hi Dm!

Ok, are you saying that the GPU will use more watts than the CPU?

Soar

[Dark Mantis]

Yes certainly. Usually much more. Especially if you have them in SLI or crossfire configuration.

[soarwitheagles]

Yes certainly. Usually much more. Especially if you have them in SLI or crossfire configuration.

Wow!  Just goes to show you how ignorant I am!  I had no clue that was the case.

Thanks for the understanding!

In my mind, I always thought the CPU was the biggest energy guzzler!

Soar

[Wonderwrench]

Thanks again Bill!

Ok, just measured my AMD rig and it is drawing 123 watts at idle, 150 watts when I surf the internet, and 200 watts when I watch a movie.

I am not sure what software to use to test full load.  I am not comfortable downloading OCCT PSU test software because it comes out of Russia.

Are there any other software programs I might use to test at full load?

I never realized the number of watts can fluctuate so widely as I do different tasks on the rig.  Very interesting!

Do you know what is really funny?  I have two brand new Galaxy GTX 480 1.5 MB Super Overclocked GPU's and each one idles at 222 watts, and suck 425 watts at load.  When I read that I decided to not use them!  I'd have to work overtime just to pay my electrical bill!

It would be nice to discover how many watts my GTX 460 is gobbling up!

Well, I am done with measuring the AMD rig for now.  I'll measure the Intel rig later.

Thanks again!

Soar

OCCT is the only all in one program I know of as it can load the CPU and GPU at the same time. I have used it for years without problems. You could use IntelBurnTest and MSI Afterburners Kombustor or Furmark at the same time. Keep in mind no matter what you use you must keep an eye on your temps. I would only run the test long enough to get the results.

Bill