Justifying buying a lower wattage System

[Mitch101]

Im trying to justify purchasing a lower powered PC.

Lets say my current system is a AMD 955BE and I switched to a i5 3570K - forget overclock and everything else right now and lets assume every other component were the same like memory, hard drives, etc. Lets assume the mobo draws the same power.

If I left it on 24x7 how much would the i5 3570K save over the course of a year over the AMD 955BE?

Anyone got a chart to what a typical PC like these cost to run a year? Maybe I can compare the two wattage wise for a year and then determine the cost difference?

Im also considering the secondary cost like Air Conditioning Running in the summer but that might be going too far as it might offset by the heat generated in the winter months however I think cooling might cost more.

Thoughts, Charts, Links?

 

[frozentundra123456]

Im trying to justify purchasing a lower powered PC.

Lets say my current system is a AMD 955BE and I switched to a i5 3570K - forget overclock and everything else right now and lets assume every other component were the same like memory, hard drives, etc. Lets assume the mobo draws the same power.

If I left it on 24x7 how much would the i5 3570K save over the course of a year over the AMD 955BE?

Anyone got a chart to what a typical PC like these cost to run a year? Maybe I can compare the two wattage wise for a year and then determine the cost difference?

Im also considering the secondary cost like Air Conditioning Running in the summer but that might be going too far as it might offset by the heat generated in the winter months however I think cooling might cost more.

Thoughts, Charts, Links?

It would depend on whether the 24x7 was at full load or not. The 3570K is rated 77w while the 955 is 125 watts. So at full load you might save call it 50 watts x 24 hours or 1200watt hours or 1.2kwhr. So maybe 15 cents per day, which doesnt sound like much, but over a year, could be 50.00.

Realistically though, the CPUs would not be running at full load all the time, so the savings would be less. From a monetary standpoint, CPU power usage becomes a much bigger factor if overclocking I would think, or in this case, you would have to overclock the 955 to reach the performance of the 3570, so it could use a lot more power if you overclock to reach the performance of the 3570.

 

[Ken g6]

Im also considering the secondary cost like Air Conditioning Running in the summer but that might be going too far as it might offset by the heat generated in the winter months however I think cooling might cost more.

You're right that cooling costs more. But as long as you're generating heat, might as well continue until the warmer months come back. Haswell should be out by then too, and it's supposed to be even more efficient.

 

[Mitch101]

Thankyou for the reply

At $50.00 for a year only under full load Im thinking thats not enough to justify the cost difference between them but I think it is worth knowing and considering. My guess is its probably closer to a dollar a month difference.

My kids leave their computers running all the time. I just put them on power savings modes but wanted to estimate how much they are wasting by leaving them on and if it was worth upgrading them to cut costs and if it would be effective.

I also wanted to justify a personal upgrade too but this wont cut it.

Same with me replacing the lights they leave on with LED ones also because of the mercury if they break one.

Im starting to sound like my dad did you live in a barn but able to come up with ways to make it work.

 

[Mitch101]

You're right that cooling costs more. But as long as you're generating heat, might as well continue until the warmer months come back. Haswell should be out by then too, and it's supposed to be even more efficient.

Thanks for the reply too.

I got that Idea from snow lodges that use outside air in the winter instead of compressors for their refrigerators. They were all around a bar one night drinking on the coldest day of the year and heard the compressors kick on to cool the walk in fridge didnt make sense to pay when the outside air could do it for less.

 

[ShintaiDK]

Idle or 100% loads?
Do you use AC in the room?
What do you pay per Kw/h?
Whats the efficiency of your PSU?

There are also a few differences. The platform will use less power as well. The AMD platform is a 2 chipset design with the PCIe hub externally. LGA115x is a singlechip design with integrated PCIe.

You can roughly compare here:
http://www.anandtech.com/show/5771/the-intel-ivy-bridge-core-i7-3770k-review/20

Using the 975BE vs the 3770K should roughly give you the same difference as 955BE vs 3570K. So 30W idle and 50W load in savings would be a good estimate. Not to mention the speed increase in the 50-100% range.

In Denmark the savings in power for 24/7 operation and no air conditioning would be 101$ for idle mode and 168$ a year in savings.

(0.384$ per Kw/H)
www.energy.eu

But again, you are comparing apples to oranges with 955BE vs 3570K in terms of speed.

Our household here with HTPC, 55" LED TV, stereo, all household appliances including tumbler, lights, laptop, 2 gaming PCs only uses 3Kw/h a day.

 

[Idontcare]

Thanks for the reply too.

I got that Idea from snow lodges that use outside air in the winter instead of compressors for their refrigerators. They were all around a bar one night drinking on the coldest day of the year and heard the compressors kick on to cool the walk in fridge didnt make sense to pay when the outside air could do it for less.

Modern society is about convenience, not energy conservation.

Yes that winter air could shoulder the work of keeping your fridge contents frozen, and you'd think it was an awesome idea until that first time an unexpected warm snap hits your freezer and you come home from work to a freezer full of defrosted beef.

History tells us exactly how to be more efficient, use bikes instead of cars, use lake ice instead of refrigerators, winter in Florida and summer in Maine, etc...but the reason we abandoned those tried and true methods is because they weren't practical in comparison to the ease of life at the hands of affordable and dependable electricity.

When it comes to replacing a computer on the basis of electrical savings alone you are going to be hard-pressed to make that case.

Your situation is kind of like that of a person who wants to make the case for buying a brand new car because the new car will have better gas mileage. Even if you were swapping out a Hummer for a Prius you are not going to save money in the equation.

 

[VirtualLarry]

I recently went through this. I had been running a pair of Q9300 @ 3.0 quad-cores.

One main rig with a GTX460 1GB, and one secondary with HD4850. Both running DC 24/7.

My electric bill started to get extreme. (Granted, that was likely because of the A/C, not the computers.)

But my KAW estimated that my main rig would cost $289 per year.

That's when I decided to act, and put together a low-power rig.

I bought a $60 E-350 mobo off of Newegg, a $30 micro-ATX case, and a $30 PSU from Staples (Antec 300W).

Total wattage for that rig was under 50W at the wall, and around 36W idle.

But I found that it was a bit too slow for my needs.

So Staples had a slimline G630 Gateway system for $200 + tax AC. So I bought that one too.

The G630 has more CPU power, and about the same idle wattage as the E-350.

I replaced the HD with an SSD. Runs pretty good.

If you're interested in my E-350, I could part with it for $300, incl. SSD.

 

[Ferzerp]

It's really never a sound economic decision to replace any system with a new one because it uses less power (at most reasonable power costs).

If you're buying a new system anyway, sure, make it a factor if it matters to you.

 

[ShintaiDK]

It's really never a sound economic decision to replace any system with a new one because it uses less power (at most reasonable power costs).

If you're buying a new system anyway, sure, make it a factor if it matters to you.

It should always be a factor when you buy new. Wasted electricity(Or any other utility) is just setting your $$$ on fire.

 

[Ferzerp]

It should always be a factor when you buy new. Wasted electricity(Or any other utility) is just setting your $$$ on fire.

I always buy purely for performance. It would require exactly equal performance for power usage to factor in to my purchase

Battery powered systems are different.

 

[Zap]

My kids leave their computers running all the time. I just put them on power savings modes

Besides leaving power savings enabled and the CPU at stock clocks, see if the motherboard allows undervolting.

Also, enable S3 sleep mode and set Windows to go to sleep after 10 minutes or so. In such a sleep mode, the computer is essentially off as far as power consumption is concerned.

 

[2is]

Buy an SSD and turn the computers off when not in use. You'll save more money that way in addition to spending less for a whole new system and you accomplished that while giving your computer a significant upgrade. There's really no reason to keep it on unless its a server of some sort.

 

[Lonyo]

Buy an SSD and turn the computers off when not in use. You'll save more money that way in addition to spending less for a whole new system and you accomplished that while giving your computer a significant upgrade. There's really no reason to keep it on unless its a server of some sort.

Or just use sleep mode...

 

[Yuriman]

Your situation is kind of like that of a person who wants to make the case for buying a brand new car because the new car will have better gas mileage. Even if you were swapping out a Hummer for a Prius you are not going to save money in the equation.

I'll give the H2 the benefit of the doubt and assuming 12MPG. I'll also assume you drive 15,000 miles per year like the average American. Gas is currently $4 per gallon where I live in the US.

Each year the H2 will use 1,250 gallons of gas. That's $5000 per year in fuel.

A Prius C is ~50MPG and has an MSRP of $19,000. You'll use 300 gallons of gas per year and spend $1200 per year.

Assuming gas prices don't rise (lol) and you pay full MSRP for your Prius, you'll pay for your Prius in 5 years in the US. If you live in Europe, you'll pay for it in 2.5 years, and after 5 years you've bought yourself a second Prius. Your first Prius only has 75,000 miles and has excellent resale value.

Granted, there are differences in utility, but still....

@OP, depending on where you live it can be very worthwhile.

 

[SPBHM]

you can underclock/undervolt the PII X4 and get some good results,
if the PC stays most of the time idle, you can make a custom more aggressive idle power mode and I think power usage in idle will not be a lot worse than the newer CPUs...
also as said above, try using sleep mode S3 (suspend to ram), it works really well...
my current PC is using 55w idle, in sleep mode my power meter gives me less than 1w, and in a couple of seconds I'm back using the OS if I need....
my underclocked athlon 64 X2 uses less than 40 idle, and with the undervolt (keeping the default clock) I reduced the power usage in load by 30+W

 

[Arkadrel]

@Mitch101

Make sure your CPU is throttleing down when idle.
Download something like Cpu-Z and look at how fast its running when your in idle.

Then download K10stat, and tinker with undervolting your AMD 955BE (lower its speed/voltage when in idle).
AMD gives more volts on cpu than it needs, which can usually cut down watts used by quite a bit.

The 3570K is rated 77w while the 955 is 125 watts. So at full load you might save call it 50 watts x 24 hours or 1200watt hours or 1.2kwhr. So maybe 15 cents per day, which doesnt sound like much, but over a year, could be 50.00.

How many people spend all 24hours a day at max load?
Id "guess" its closer to like 3-6 hours a day.

Which means over a "year" instead of being 50$, its closer to ~13$ or so.

Id your useing 300$+ on a CPU/MB, to save ~13$ a year.... yeah long time until that pays back.


---------------- people saying SSD's:

HDD (mechanical) = ~5watts idle, 7watts on load.
SSD = ~0.5watts idle, 2watts on load.

SSD's wont save most people a ton of money in power either.
Yes they do use less than a normal HDD does, but it watts saved wont pay back the cost of a SSD anytime soon.

 

[2is]

@Mitch101

Make sure your CPU is throttleing down when idle.
Download something like Cpu-Z and look at how fast its running when your in idle.

Then download K10stat, and tinker with undervolting your AMD 955BE (lower its speed/voltage when in idle).
AMD gives more volts on cpu than it needs, which can usually cut down watts used by quite a bit.

How many people spend all 24hours a day at max load?
Id "guess" its closer to like 3-6 hours a day.

Which means over a "year" instead of being 50$, its closer to ~13$ or so.

Id your useing 300$+ on a CPU/MB, to save ~13$ a year.... yeah long time until that pays back.


---------------- people saying SSD's:

HDD (mechanical) = ~5watts idle, 7watts on load.
SSD = ~0.5watts idle, 2watts on load.

SSD's wont save most people a ton of money in power either.
Yes they do use less than a normal HDD does, but it watts saved wont pay back the cost of a SSD anytime soon.

My SSD recommendation wasn't to reduce power, but to make the load times much faster so that turning the computer off is less in an inconvenience.

 

[beginner99]

I'll give the H2 the benefit of the doubt and assuming 12MPG. I'll also assume you drive 15,000 miles per year like the average American. Gas is currently $4 per gallon where I live in the US.

Each year the H2 will use 1,250 gallons of gas. That's $5000 per year in fuel.

A Prius C is ~50MPG and has an MSRP of $19,000. You'll use 300 gallons of gas per year and spend $1200 per year.

Assuming gas prices don't rise (lol) and you pay full MSRP for your Prius, you'll pay for your Prius in 5 years in the US. If you live in Europe, you'll pay for it in 2.5 years, and after 5 years you've bought yourself a second Prius. Your first Prius only has 75,000 miles and has excellent resale value.

Granted, there are differences in utility, but still....

@OP, depending on where you live it can be very worthwhile.

No interested in checking your calculations but H2 to Prius is pretty much the most extreme case.

Anyway if you actually have an interest in "saving the world" and care about the environment, getting a new car is newer, ever a good idea even if you own an H2. Approx. Half of the energy a car uses in its life-cycle is it's production. So getting something new (=increasing demand -> more production) is never environmental-friendly.

And I'm pretty sure same case can be made for almost any appliance that is replaced before the end of its life-cycle.

However if the only thing that matters is cost, it can be viable but it is never ever environmental-friendly.

 

[kalrith]

I calculated this in the past, and for me it costs about $30/year to run my 40W (at the wall) HTPC on idle 24x7x365 at 9 cents per kWh. That doesn't take heat into account at all, but I would guess that it balances out since I run my A/C half the year and my heat the other half.

Anyways, if your electric costs the same as mine, then you would save 75 cents per year for every watt you can decrease your system. So, if you decrease from 120W to 40W (at the wall), then you would save $60 in electricity every year. If it costs $300 to switch systems, then it would take a full 5 years to recoup the electricity costs. These numbers just take idle usage into account. If you game for 4 hours per day, then you'll have to add that to the formula. I had a spreadsheet for all this, but I don't have it on my work computer.

When I built my HTPC, I had to build the system from scratch, so I went for a low-wattage system. If I already had a high-wattage system, then it would be a lot harder to justify the up-front expense that would take years to recoup (if ever).

 

[KingFatty]

Buy and use a Kill-a-watt power meter, so you can plug your power strip into it and literally see how much electricity your computer uses.

Should be able to find one for around $16 online.

Then, plug in your computer and start playing with the power savings, or even underclock/undervolt it. Then you can literally see the power meter change and get that nice feeling of making savings.

I remember when I first got my power meter, I went all around the house seeing what different things used. I was really surprised to see that the receiver on my home theater system was sucking down some juice when not in use, so I make sure it's turned off when not in use (instead of letting it idle). I was also surprised at how much better my newer computer was at idling compared to older computers, which I've now decomissioned. It's just all around helpful to give you an idea of what's worth leaving on and what's worth turning off. Otherwise you are making guesses.

 

[ShintaiDK]

One of the biggest powerhoggers besides AC is the fridge and freezer. Make sure its a modern power efficient one and not some 10 year old one.

 

[MrK6]

The most efficient way to be efficient is to buy with that concept in mind. Unless electricity is very expensive where you live, most times it takes a long while to recoup the costs of buying a part strictly to use less power. That said, if you're upgrading for performance, build an efficient setup from the ground up. That includes an efficient PSU, CPU, video card, and minimal mechanical HDD's. From there you can undervolt/underclock if you desire more.

 

[Lonyo]

My SSD recommendation wasn't to reduce power, but to make the load times much faster so that turning the computer off is less in an inconvenience.

Sleep mode is much faster than an SSD.
My laptop takes ~13sec to boot. (SSD)
My HTPC takes ~2sec to come out of sleep mode. (mechanical).

 

[aigomorla]

u would rescue a homeless bunny every 15 days...

no but being serious, the cost in wattage is very small.
So small, that if u had a space heater on for 1 hour, you'd probably eat into the power savings you had by swaping systems.

OR the cost in the machine upgrade, would eat the savings you had on the power cost without a noticable improvement in the dailies activities you did on the two machines.