Need suggestions on lowering Power Draw: change psu?

ryboto · Post by **ryboto** » Thu Jun 21, 2007 3:34 pm

My system is currently running as follows:
Opteron 170 2.1ghz, 1.1vcore
2gb Crucial @ ddr466 2.7v
X1950pro
1xWD raptor 150gb
1xWD5000AAKS
Hauppage PVR 150
Abit AT8 32x
2xScythe S-Flex @ 800rpm
1xoptical drive
FSP Forton Zen 400W

For other details, check the link in my sig. My issue is the idle and load power draw from the pc. I've used a kill-a-watt meter to measure draw from the wall. What's strange is that power draw has increased since I last modified the system. It's strange because since the last change, I've actually removed components. I originally had a wireless card and an ati theater 550pro. The 550 I traded for a Hauppage. The hauppage runs relatively cool, but the 550 pro would heat up the entire top rear of my case. With those two installed, and my system undervolted, from the wall, with full cpu load, the system drew 100-110W. Now, after the removal of the wireless card, the system draws 120-130W. Idle, the system draws 88-90W. If I underclock, using the 4x multiplier, giving my cpu an effective speed of 800mhz, the idle draw goes down by 1-2W.

The three things that have changed:
1.)swapped 550pro for hauppage pvr 150
2.) removed wireless card
3.) installed FSP Zen 400W

Could the Zen be less efficient at this load than my previous Enermax Noisetaker? I've tried running the system with only the onboard USB and SATA(disabled network controller and 1394 controller) and the system draw only changes by 1-2W. I know the X1950pro is going to draw a bit, it's unavoidable. If I assume ~80% power supply efficiency, The respective load and idle power draw is approximately 104W and 70W. Does this sound right? And even if it does, can anyone make sense of the fact that my power draw increased?

Thanks!

edit: I have also tried underclocking the video card when I'm just viewing 2D using ati tray tools. If I try to use atitool, the pc immediately locks up, or I get artifacting on screen when I change the clock speed. Regardless, I was able to reduce clock speeds by 300mhz core, and 400mhz mem, but it didn't seem to make a dent in idle temperatures or idle power consumption.

bonestonne · Post by **bonestonne** » Thu Jun 21, 2007 5:37 pm

you could put the 500gb WD drive in an external housing.

other than that, a more efficient power supply would help, but it already being a FSP, you're almost as efficient as it gets.

when underclocking and all that, wattage wont change, just whats used by the PC, not necessarily whats drawn from the wall.

i think that it might be the X1950, but i doubt you'll want to change that....the idle wattage and load wattage are pretty low..how low can you honestly go before you just need to realize the limits?

ryboto · Post by **ryboto** » Thu Jun 21, 2007 5:41 pm

bonestonne wrote: i think that it might be the X1950, but i doubt you'll want to change that....the idle wattage and load wattage are pretty low..how low can you honestly go before you just need to realize the limits?

I still don't understand why the power draw is greater now. I can't wait for the day GPU's get software control similar to CnQ.

prodeous · Post by **prodeous** » Thu Jun 21, 2007 10:35 pm

It is possible that the efficiency of the power supply has changed.

Since removing components does not add but remove load.

Remove the hauppage pvr 150 and check the power consumption when its removed. This would permit to exclude or include it as part of the increase of the power.

As for the new PSU, there is awlays possibility that it could be less efficient. drop of 5% efficiency with possible increase with the swap of hauppage could account for the change.

ryboto · Post by **ryboto** » Fri Jun 22, 2007 11:19 am

I'll check with the Hauppage card when I get home. I just had an extreme thought though. what if I ditched the Zen all together? Lets say the Zen is ~80% efficient at the low load I'm putting on it. My system only draws 100W under full cpu load. I'll do some tests to show CPU+GPU load, but it will be under 150W. Could I consider the PW-200-M DC-DC power supply? A pico psu cousin? I did the math, and after all is said and done, I can return the Zen, buy the PW-200-M and a Dell 220W adapter on ebay and i'll get back a few dollars! Does anyone think it would work?

angelkiller · Post by **angelkiller** » Fri Jun 22, 2007 5:09 pm

ryboto wrote:I still don't understand why the power draw is greater now. I can't wait for the day GPU's get software control similar to CnQ.

Actually some cards have separate clocks for 2D and 3D applications. So when doing nothing, the card would downclock it self, and when you load a game or whatever, it clocks it to it normal clocks. The only way I know to do this is by flashing the GPU's BIOS. And I tried it on my X1950pro, and it didn't have 2D & 3D speeds.

Just wanted to say that it was possible.

ryboto · Post by **ryboto** » Fri Jun 22, 2007 6:09 pm

angelkiller wrote: Actually some cards have separate clocks for 2D and 3D applications. So when doing nothing, the card would downclock it self, and when you load a game or whatever, it clocks it to it normal clocks. The only way I know to do this is by flashing the GPU's BIOS. And I tried it on my X1950pro, and it didn't have 2D & 3D speeds. Just wanted to say that it was possible.

I know it throttles clock speeds, but that only seems to have an affect on gpu temperature, and not power consumption. I know this, because I've manually underclocked the card, and idle power draw doesn't change.

angelkiller · Post by **angelkiller** » Fri Jun 22, 2007 7:53 pm

ryboto wrote:I know it throttles clock speeds, but that only seems to have an affect on gpu temperature, and not power consumption. I know this, because I've manually underclocked the card, and idle power draw doesn't change.

Interesting. Maybe you have to alter GPU voltages

:? Sorry, I'm out of ideas.

ryboto · Post by **ryboto** » Fri Jun 22, 2007 8:08 pm

angelkiller wrote: Interesting. Maybe you have to alter GPU voltages :? Sorry, I'm out of ideas.

right, that's the obvious conclusion. Can ati tray tools do this? Or would I be forced to edit the bios?

ryboto · Post by **ryboto** » Mon Jun 25, 2007 6:38 am

So, I've still got the question about using a 200W PW-200-M/V. I stress tested the system using atitool/Orthos/watching a dvd in the optical drive and a video from one of my hard drives, and the draw from the wall was 180W. If I assume ~80% efficiency, that's a draw of 144W, within the power output of the PW-200. If you're unfamiliar with it, it's a cousin of the Pico psu. It costs more per watt, but I would free up a lot of space. I could move my hard drives so that they're both in the path of airflow. Also, I imagine it might be more efficient as well, considering the brick I would buy(220W Dell) would be operating between 50-70% of it's peak output. I'm not sure how much longer I have before I can't return the Zen, so, I'm looking for opinions. Is it doable? Would it be worth it, or should I just continue to use the zen?

ryboto · Post by **ryboto** » Tue Jun 26, 2007 4:59 am

so, does anyone have any opinions about the power brick route?

ryboto · Post by **ryboto** » Tue Jun 26, 2007 6:17 am

Or, is it worth exchanging for a 300W zen? I can probably get nearly all of my money, and even avoid a restocking fee if i act soon.

ryboto · Post by **ryboto** » Wed Jun 27, 2007 10:35 am

I hate to keep bumping this thread, but I need some advice/input/suggestions soon, or I wont be able to return the Zen.

mttcrlsn · Post by **mttcrlsn** » Wed Jun 27, 2007 12:51 pm

I am not familiar with the Zen power supplies (never worked with one), but I would say that it may be faulty.

Don't know if this is any help but I have used the Power Calculator to ballpark what systems should average in draw.

mttcrlsn · Post by **mttcrlsn** » Wed Jun 27, 2007 12:52 pm

Ok so I am new here and could not post the URL for the Power Calculator.
Here it is: http://www.extreme.outervision.com/psuc ... orlite.jsp

ryboto · Post by **ryboto** » Wed Jun 27, 2007 1:23 pm

I already have a Kill-A-Watt meter, so I can measure the draw. The system never pulls more than 180W from the wall. Since that's the case, I could get away with using a PW-200-M/V. The cost would be greater, but I can move psu heat outside the case, and free up space inside the chassis. Does anyone thing I should switch power supplies?

jaganath · Post by **jaganath** » Wed Jun 27, 2007 3:33 pm

If the 400W Zen is as efficient as the 300W Zen, it's hard to imagine you would get a large efficiency gain from going to the PW200M. Also you say your maximum power draw is within the capabilities of the PW200M but really it's right on the edge; OK, you won't see that very often and maybe if it just passes the 12V through as the Pico does you will be okay but still....

one option would be to swap the Zen for a SS-300SFD and run it fanless, that's about the only conventional PSU that has a higher efficiency than the Zen at your typical power draw. returning the 400W for the 300W should mean you are operating the PSU at a slightly more efficient point on the power curve.

ryboto · Post by **ryboto** » Wed Jun 27, 2007 4:03 pm

jaganath wrote:Also you say your maximum power draw is within the capabilities of the PW200M but really it's right on the edge; OK, you won't see that very often and maybe if it just passes the 12V through as the Pico does you will be okay but still....

well, the PW-200-M just passes the 12v through, I still think it can't handle greather than 200W total output. Since my system only draws a max of ~185W, completely loaded from the wall, it's true DC draw from the psu(if 80% efficiency is assumed, which might be an overestimate) is 148W. That would load the PW-200-M to 74% of it's output.

jaganath wrote: Returning the 400W for the 300W should mean you are operating the PSU at a slightly more efficient point on the power curve.

I'll have to consider the Zen 300W....my only complaint is that it's exhaust is a very restrictive vent, while the 400W model has a large area for air to flow. The 400W say's it's 80plus certified on the box, so, under full load ~100W DC draw, I'm above the 20% line, so it should be in the 80's...I don't know what to do...I think I have a week or so before I can't return it, the 300W zen would be cheaper than keeping the 400W, as well as acquiring all the parts for a PW-200-M to work.