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Silly power requirements, an over hyped myth?

Tom|Nbk said:
The Vcore has to be set to Auto afaik no way around it, and EIST is automatically enabled I think with my borad and I had enabled C1E yes, then I changed the power profile in Windows and it worked fine (lowered clocks on idle) but the Vcore stayed the same deeming it pretty useless. :(
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I think the Speedstep option at the bottom here is the EIST.



Don't know if you've seen this, but there's a program that lets you play with the FID/VID options. Although I think you're still stuck with the Vcore=auto for any EIST, dunno never tried, but VID should step down.

http://cpu.rightmark.org/


 
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Well a chip running at 2ghz will use less juice than a chip running at 3ghz, even if the vcore is the same, so the speedstep helps a little.

What is needed really is some software that will automatically adjust the vcore depending on the CPU speed. :) You could tell it what vcore it needs to be stable, then the proggie could adjust it automatically - speedfan styley. :cool:
 
MikeHunt79 said:
Well a chip running at 2ghz will use less juice than a chip running at 3ghz, even if the vcore is the same, so the speedstep helps a little.
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Speedstep is supposed to change VID, variable Vcore with variable frequency FID. That's the theory anyway.

MikeHunt79 said:
What is needed really is some software that will automatically adjust the vcore depending on the CPU speed. :) You could tell it what vcore it needs to be stable, then the proggie could adjust it automatically - speedfan styley. :cool:
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Profiles in the Pro version by the looks of it. Don't think it overvolts though.

 
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The problem with a HD2900XT/8800GTX is that it has an awful lot of transistors so at idle they still use a lot of power.

I also have a wattage meter and the difference at idle between my old 7800GT and my 8800GTS is ~40W (AFAIR)

Also motherboards use a lot more power than they used to.

I think the last time I checked my machine was close to 400W at load as well, after having to pay 600 euro's extra to the leccy company I decided to just turn off the damn machine when not in use instead of leaving it idling.
 
Lanz said:
Many people do leave their PCs on tho, and those nutters who think they are saving the world, folding for cancer or trying to find aliens, I'm sure if they turned their PCs off, it would help the world much more :)
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Yep, I used to be one of those until I realised having 3 overclocked w/c x-fire rigs running 24/7 was sheer madness.

They get switched off now when not in use.
 
It's not a simple matter of watts, its how many amps your pulling and at what votage.
What your paying for in high performance PSU is how many amps it can supply on 3.3v,5v and 12v rails for long periods and remain stable.
Be carful when buying cheap PSU some will provied enough power but have short life spans,poor efficiency and so, some have been known to just blow up and kill your whole rig.
 
Incidentally dell qualified their 375w psu (440w load) on their 9200 dimension to run an x6800, 8800gtx, x-fi, tv card, 2 sata hard drives, 2 optical drives, 3 fans and a bunch of usb devices. Not sure how much power this actually drew but the psu was kind of hot and ran almost full whack. Still worked 24/7 for over 6 months for me with no issues.
 
jigger said:
It's not a simple matter of watts, its how many amps your pulling and at what votage.
What your paying for in high performance PSU is how many amps it can supply on 3.3v,5v and 12v rails for long periods and remain stable.
Be carful when buying cheap PSU some will provied enough power but have short life spans,poor efficiency and so, some have been known to just blow up and kill your whole rig.
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Yup, I had an old K6 based pc (with a voodoo 3xD) that had a capacitor blow on the psu a few months back, taking everything with it(optical drives and all :eek:).

Anyway, on topic :p
It's becoming fairly obvious that the r600's power 'rquirements' were a bit overblown. My powercolor came with a recommendation of a 500w psu with 30amps on the 12v rail (instead of a 750w psu :rolleyes:
 
Tom|Nbk said:
Ok the 3D Mark results are in, the power usage remained between 370-400w the highest it peaked was 400w and it only stayed there for a split second this was on Canyon Flight and in the cpu tests the power usage remained around 350w. Im fairly suprised and I will do more tests with various different games to see how it affects the power usage. All in all 400w is impressive, just shows you can most likely get away with a 2900xt on a 450w with decent railage and still have a nicely oced C2D.


cimg0317pe0.jpg
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now im sure that the hiper psu has around 75% efficiency so that means if your pulling 400w from the mains the power the actual components are pulling from the psu is 25% less than the wall socket which means your system has a 300w power draw.??? seems to be low to me.
 
Cyber-Mav said:
now im sure that the hiper psu has around 75% efficiency so that means if your pulling 400w from the mains the power the actual components are pulling from the psu is 25% less than the wall socket which means your system has a 300w power draw.??? seems to be low to me.
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Cyber-Mav can your meter show how many amps your using, could be interesting
 
Tom|Nbk said:
Ok the 3D Mark results are in, the power usage remained between 370-400w the highest it peaked was 400w and it only stayed there for a split second this was on Canyon Flight and in the cpu tests the power usage remained around 350w. Im fairly suprised and I will do more tests with various different games to see how it affects the power usage. All in all 400w is impressive, just shows you can most likely get away with a 2900xt on a 450w with decent railage and still have a nicely oced C2D.


cimg0317pe0.jpg
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Sorry(last post) same question to Tom|Nbko
 
jigger said:
It's not a simple matter of watts, its how many amps your pulling and at what votage.
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That's funny ;) , you just defined wattage.
Cyber-Mav said:
now im sure that the hiper psu has around 75% efficiency so that means if your pulling 400w from the mains the power the actual components are pulling from the psu is 25% less than the wall socket which means your system has a 300w power draw.??? seems to be low to me.
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The efficiency curves aren't linear, could be even worse depends on the load point. They tend to quote the highest efficiency point.
 
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Cyber-Mav said:
now im sure that the hiper psu has around 75% efficiency so that means if your pulling 400w from the mains the power the actual components are pulling from the psu is 25% less than the wall socket which means your system has a 300w power draw.??? seems to be low to me.
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Seems spot on to me :confused:
 
Boogle said:
Watts / Volts = Amps.

So 396 / 230 = 1.72 amps.

Amps * Volts = Watts.

Rearranging equations ahoy!
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That assumes the PSU has PFC, i.e. power factor = 1 (unity) otherwise the current is higher. It use the apparent power in volts x amps

Real power (W) / PF = Apparent power (VA)

Say it measured 396W at PF=0.9 230V.

396 / (0.9 x 230) = 1.91A
 
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