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Suggestions: High performance low power system

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April 23, 2009 6:07:43 AM

I want to build a new system for gaming.
I want some decent performance e.g. Crysis at 1900x1200 at high settings (may not need to be highest).
However I also want it to be low power (with highest performance), so I would not prefer extra fans or specialized cooling systems. (350-400W total - if possible)
No overclocking required.
Budget: Any
I do not intent to upgrade (maybe add RAM in future or change display card).
Running 32bit XP at the moment so 3-4G RAM at most, but should have a few more RAM slots for future.

To give you some idea of what I am look for, I am looking at i7 920, GTX 280 etc, DDR3 (3x1G).

Thanks in advance
April 23, 2009 6:18:28 AM

Sorry, I think you'll need much more power than 400W. In fact, I'd suggest 550W as the minimum.
April 23, 2009 6:23:25 AM

Around 400W actual power usage. I am not sure if possible. (around 550W at 80% efficiency)
Yeah I just wish GPUs would go the way of CPUs and boast low power as a feature.
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April 23, 2009 6:26:02 AM

400w is plenty to play crysis at that res. An i7+GTX 285 at full tilt midgame will consume less than that, I think you are under the impression that PC's are more power hungry than they really are.
April 23, 2009 9:43:02 AM

Yeah, I think some people think that a modern PC draws 500+ Watts because they see all these recommendations for 500+ watt power supplies. In reality, most draw less than 300, and if you really focus on cutting energy, you can easily get that under 250 at FULL load.

Here's one of many charts online(ain't google searches grand) illustrating how much a core i7 920 + GTX 280 system draws at idle and full load.

http://www.bit-tech.net/hardware/cpus/2008/11/03/intel-...

They really didn't need to use a 750 watt power supply in that setup, a 400 probably could have done the job. Of course, it's always good to have some room for future upgrades...

If you really want to focus on cutting power, you can opt for a solid state drive as your main os storage and have an external storage drive that you just plug in whenever you need more space.
April 23, 2009 12:48:39 PM

High performance and low power do not go hand in hand.
April 23, 2009 9:00:42 PM

daship said:
High performance and low power do not go hand in hand.

Well not usually, but the Q9550S is rated 65w TDP and it kicks butt...god awful expensive though.

But yeah high performance (especially in games) means higher power consumption, but your definition of low power consumption of 400w is actuall fairly high on the scale of PC power consumption, so you should redefine what you think low consumption is.
April 23, 2009 10:08:50 PM

I doubt you'll find a 400 watt PSU that can put out 40 amps on the rails. Not to rain on your green power parade but you'll only be asking for trouble trying to run a system with the GTX 285 with anything under 500 watts. Please, please check Google on the idle and full load power consumption for this card.
April 23, 2009 10:12:31 PM

hundredislandsboy said:
I doubt you'll find a 400 watt PSU that can put out 40 amps on the rails. Not to rain on your green power parade but you'll only be asking for trouble trying to run a system with the GTX 285 with anything under 500 watts. Please, please check Google on the idle and full load power consumption for this card.

I wasn't saying to use a 400w PSU, I said the system wouldn't use more than 400w. The PSU for a system like that should be like a Corsair 550vx or 650tx. A PSU does not put out its rated wattage regardless of the internals, the rating on a PSU is what it can supply. The guts of your system will determine how much power is used.
April 24, 2009 9:57:54 AM

Well, the GTX 295 is quite efficient on a full load, not so much on idle, as expected.

http://www.tomshardware.com/reviews/geforce-gtx-285,213...

The GTX 285 would be the choice for an efficient gaming system on idle.

With power consumption peaks around 300W-400W, a minimum psu of 500W, 80Plus certified, is technically enough. But i would go with a 600W for the GTX 295 to be safe.
April 24, 2009 3:40:24 PM

Unless you bought a FULL version of XP you can not transfer it. So if you have bought OEM XP separately or bought a prebuilt system then it's tied to that computer. If you have a FULL version and transfer it then your old system has no OS which is a waste unless someone wants it for Linux.

If you are building a new PC with relatively high specs you should be getting 64-bit Vista, though I recommend getting a copy of Windows 7 RC 64bit for free on May 5th then buying Windows 7 64bit when it's finally released.

As you may see, a low-power high-end gaming system is an oxymoron.

Here's my suggestion:
(read reviews and compare prices for parts like the RAM)

- Asus M4A78T-E 790GX
- 4GB DDR3 RAM
- Phenom II X4 810
- Corsair TX650W
- graphics (maybe a single GTX 275, though I might use the onboard video and hold off for ATI's next 40nm high-end graphics card in a few months or NVidia's next card.)
- HSF for CPU: get one with a 120mm fan to replace your stock. Look at NCIX for reviews. Many to choose from. The OCZ Vanquisher might work fine. (make sure the fan has a range like 800->2000RPM or similar).

- rear 120mm low-flow (about 17dBA) fan

There's the core of your computer. There aren't any shortcuts for playing new games at good resolutions. A good 650W PSU will consume less than a poor 400W (poor can mean lower efficiency or not pairing properly with your hardware). An improper PSU will provide all kinds of headaches too.

You can't skimp on the rear 120mm fan for air flow. A proper CPU HSF will be much lower than stock (make sure fan speed is enabled in the motherboard BIOS).

Some graphics cards are quite loud. My HD3870 uses about 26W of power in Idle. Some use 90W.

Audio:
You need both a good audio card and good speakers to get good audio. Bad onboard audio and great speakers is dumb. An expensive audio card and cheap speakers is also dumb. Although slightly expensive, I'm a big fan of the M-Audio AV40 speakers paired with a good Auzentech card.

At any rate, you can purchase an addin card and better speakers later if need be.
April 24, 2009 5:07:46 PM

Something to keep in mind as the psu's capacitor's start aging the less effecent the psu will be. Psu's over time do degrade and it's important to note that. So a psu that is rated to run 800w's continuously for instance will degrade over time. The closer your running ur psu to 100% the faster the caps will age. I'd recommend running your psu somewhere between 60-75% load.
April 29, 2009 3:28:34 AM

Just to be clear, I suggested a 550W PSU to make sure you fall within the safe threshold.

In any case, azrealhk, an i7 920, a GTX 260, 3GB of RAM, one hard drive, and one optical drive will keep your power requirements relatively low, while providing good performance IMO.

I also have a related question: is the power consumption of a PSU relatively constant? Or does it wildly spike/drop depending on PC's usage?
April 29, 2009 4:05:55 AM

r_manic said:

I also have a related question: is the power consumption of a PSU relatively constant? Or does it wildly spike/drop depending on PC's usage?

I don't understand your question...the PSU itself consumes only a couple watts to power the fan and any LED's it has, and a little is lost due to power conversion and less than 100% efficiency, but a PSU doesn't need power really. Are you asking if its output is constant?
April 30, 2009 9:20:21 AM

It was more of a "how will it affect my electric bill" question. But then I realized most PCs start consuming less electricity when idle, so question answered :D 
April 30, 2009 10:33:52 AM

The PSU wastes about 20-100W of power to the wolves; that's why it has a fan anyway. All the inefficiencies will turn into heat inside the PSU, so it needs to be cooled. The more efficient the PSU is, the less cooling it needs. That's why passively cooled PSUs are often very efficient too (92%+).

If you want to build a low-power system, look at idle power when you're not using the system. A good system should run near 50W of idle power drawn. This is achieveable on a gaming system though not easily because videocards are known to waste a lot of power. While its doing absolutely nothing its cooking so hot it still needs cooling. This is ofcourse very bad, and nVidia has been known to be a bit better than ATi in this regard. Their idle power drawn is lower, and some cards support HybridPower, which turns the videocard off when you're inside windows, and lets the onboard videocard handle all 2D tasks. Only when you start gaming will your videocard be used and draw power. That would help.

Unfortunately this HybridPower option is only available in Windows Vista. They couldn't get it to work on Windows 7 reliably. Too bad.
April 30, 2009 11:49:38 AM

a good PSU will waste about 15w per 100w, so for 400w output you'll want a PSU with 460W input minimum, assuming this is a high end PSU which has 80plus silver.

so that means a good silverstone or an OCZ seem to be the best options.
April 30, 2009 11:57:45 AM

I think the question is does the overall power PSU draws from the wall plug varies with the idle/load status of the CPU/GPU. Can someone with that knowledge provide an answer?

Anyway, the rated power is not equal to the power you gets, for example, an ASUS U-65 PSU is rated for 650W, but only 540W goes to the +12V rail, which is what most components are power off of (like GPU, CPU, etc.). So do check the manufacturer's website to make sure the PSU fits your need.

EDTI: Yeah, so yes, the power draws from the wall does vary, here's a nice chart for you to see =)

http://www.80plus.org/manu/psu/psu_reports/ENERMAX_EDM6...
April 30, 2009 12:06:19 PM

dragoon190 said:
I think the question is does the overall power PSU draws from the wall plug varies with the idle/load status of the CPU/GPU. Can someone with that knowledge provide an answer?

Think about it for half a second. Yes of course.
April 30, 2009 12:08:16 PM

xthekidx said:
Think about it for half a second. Yes of course.


Yeah, I know...brain dead from too much food :pt1cable: 
May 5, 2009 3:19:52 AM

Interesting... so is it safe to conclude that the final power consumption of a PC (again, the electric bill kind of consumption), depends more on what components are used, and less on the power supply?
May 5, 2009 3:39:45 AM

Yes. The efficiency of the PSU determines how much energy is lost, the components in the PC determine how much power is used.
May 5, 2009 12:10:33 PM

Just to itterate over what thekid has stated. Yes ur electric bill will mostly be driven by the components that are inside your case and not the psu. Its not entirely driven by them though. PSU's have an efficency precentage which is important to take into consideration. So for example if your pulling 1kw from your wall and your psu is 80% efficent, your psu will be providing 800w's to your rig. The efficeny loss is due to the tranformation of electrical engery into heat mostly. Just the law's of physics at play.

Depending on your electrical engineering skills there are way's to boost the current and voltage from a wall socket (using an amplifier). This however is probally not a road you want to go down. Here's a little reading if your interrested; link. This stuff isn't the easiest to learn. The math would most likely start getting ugly due to varring ranges of input and safety would become an issue. Creating a circut that can do this does take some skill.
May 6, 2009 3:07:24 AM

Erk. Math as a prerequisite for safety will probably mean injury or death in my case :p 

So... going back to the OP... would it be best to just recommend a good 500W PSU (like say, a CORSAIR) and work within that framework?
May 6, 2009 3:28:23 AM

azrealhk said:
I want to build a new system for gaming.
I want some decent performance e.g. Crysis at 1900x1200 at high settings (may not need to be highest).
However I also want it to be low power (with highest performance), so I would not prefer extra fans or specialized cooling systems. (350-400W total - if possible)
No overclocking required.
Budget: Any
I do not intent to upgrade (maybe add RAM in future or change display card).
Running 32bit XP at the moment so 3-4G RAM at most, but should have a few more RAM slots for future.

To give you some idea of what I am look for, I am looking at i7 920, GTX 280 etc, DDR3 (3x1G).

Thanks in advance

Well back to this. I'm not sure the OP is even following this thread since he hasn't made any comments since the start of this thread, but I would build sorta like this:

Asus P6T /SE (you can spend more here, but I don't see the need. The Gigabyte Extreme has a nice onboard x-fi chipset if you are interested.
i7 920 OC to 3.2-3.6ghz can be done on stock voltage, especially if you get the newer stepping.
Corsair 650tx
A nice case that he likes the look of, preferably with some nice ventilation like the HAF 932, Antec 1200 or similar
GTX 285
WD Caviar Black 1TB
Any Sata DVD burner
6gb DDR3 1600mzh ram
Noctua NH-U12P SE 1366 Cooler, MX-2 TIM

That would run under 400w total power draw and play games at full settings at 19x12 res.
May 7, 2009 12:18:11 PM

*Claps hands* Bravo on thekid's build....I thing that is pretty solid. It would also put the psu at about 65% load which is a comfortable operating range (at least I think).
May 11, 2009 7:33:10 AM

+1 on build! Bumping thread up for everyone to see :D 
!