Just how much power do you think your system uses?

[freecableguy]

You may be surprised...

I have a Kill-a-Watt on the way but my calculations on total power consumption for my system is quite high. In fact, for those that think a PCP&C Turbo-Cool 510 SLI can handle overclocked/over-volted dual 512MB 7800GTX GPUs and a highly OC'ed FX-57 may be in for a rude awakening.

Assuming an FX-57 CPU at 110W full load TDP...

Now overclock to 3.6Ghz with 1.65v...
110*(3600/2800)^2*(1.65/1.4)= 214W

Assuming 7800GTX 512MB cards in SLI overclocked to 700Mhz core/1.65v...
2*80W*(700/550)^2*(1.65/1.5)=285W

Stock speeds: 110+160=270W which is completely managable by today's standards for PSU purchases.

Overclocked: 214W+285W=499W for CPU and GPU's alone...now add the motherboard, the memory, the sound card, the optical drives, HDDs, fans (eastly 10W each on average) and maybe a waterpump (20-30W nominal) and we can see that the once believed over conservative PSU rated in the 500-600W range is NOT enough.

For those running stock systems with stock clocks, there's a reason that nVidia certifies some manufacturer's PSUs as SLI ready. Just remember, those that have the "monster" PCP&C SLI 510W (630W peak?) may find themselves in situations where it can't provide enough juice in high-load applications (think 3D gaming at high-resolutions with full sound and eye-candy on).

I know that my system will stutter and then crash to the desktop while playing 3D games with a PCP&C 510 whereas my 1kW unit charges along.

Maybe the PCP&C 850 SSI and 1kW units aren't so "unneeded" afterwards..

http://www.pcpowercooling.com/produc...php?show=TC1KW

-FCG

[[XC] leviathan18]

820w is more than enough i dont think we will need more than that with the new trend of perfomance per watt

[physics_geek]

560W is MORE than enough! even for 2x7800GTX 512MB

[uOpt]

Even with mad overclocking and my least efficient PSU (the OCZ) I cannot get the bse machine (no graphics) much about 220W dual-prime load with E6s, X2 or Opteron 939s.

My 3400+ with 6800 Ultra draws 300 watts max.

All powermetered.

[freecableguy]

560W is MORE than enough! even for 2x7800GTX 512MB

Well, $hit, what a great argument. Totally blows my calculations out of the water. Your statement has so much merit, too. Thanks for explaining this to me. I'll go back to eating dirt now.

[Delirious]

Well, $hit, what a great argument. Totally blows my calculations out of the water. Your statement has so much merit, too. Thanks for explaining this to me. I'll go back to eating dirt now.

lmao

So is the OCZ 520 powerstream an inefficient power supply?

[onewingedangel]

The problem is that the power draw doesnt scale linearly with clockspeed or voltage used, so your calculations are inherantly flawed.

Measuring the actual system power draw is however a pretty accurate way of measuring what kind of power requirements your system needs.

[Tim]

I'm really wondering what this has got to do with news...just trying to get the most views maybe?

[saaya]

the fx57 doesnt consume over 200W kris, never...

[HKPolice]

http://techreport.com/reviews/2005q4.../index.x?pg=13



System had a 4800+, 2GB ram and 1 HD
I'd say that an 800watt PSU would be the MOST you'll ever need.

[Mr. Tinker]

Just wait till you get your kill-a-watt. You may be in for a surprise. I think your overclocking power consumption calculations are a bit too simple.

[freecableguy]

http://techreport.com/reviews/2005q4.../index.x?pg=13



System had a 4800+, 2GB ram and 1 HD
I'd say that an 800watt PSU would be the MOST you'll ever need.

So, if 400W is 2x 7800GTX 512MB and a 2.4Ghz 4800+ all at stock speeds...then what does this mean for GPU's running at +150Mhz core and +250Mhz (eff) memory and an FX-57 at 3.6Ghz+???

Still think 500W is off base?

Also, looks at the delta between 7800GTX 512MB to Dual cards...407-274W would suggest (although I know this is not a completely true calc) that a SINGLE 7800GTX 512MB card consumes about 130W at FULL LOAD. So my calculation based on 80W per GPU in stock form may actually be very conservative.

-FCG

[HKPolice]

So, if 400W is 2x 7800GTX 512MB and a 2.4Ghz 4800+ all at stock speeds...then what does this mean for GPU's running at +150Mhz core and +250Mhz (eff) memory and an FX-57 at 3.6Ghz+???

Still think 500W is off base?

Also, looks at the delta between 7800GTX 512MB to Dual cards...407-274W would suggest (although I know this is not a completely true calc) that a SINGLE 7800GTX 512MB card consumes about 130W at FULL LOAD. So my calculation based on 80W per GPU in stock form may actually be very conservative.

-FCG

Ya, but 1kW is still overkill. 800 would be more than enough. Those measurements were taken from the PSU's power cord, so minus the inefficiencies of the AC/DC conversion, and you're left with maybe 350watts max draw from all the hardware components. Even if you DOUBLE that under overclocked situations, which will never happen, 700watts actual draw = 800watt PSU max.

No, a single GTX 512 will not use up 130watts by itself because the dual core CPU would be under more strain when running in SLI, adding to the delta figure.

Why is this thread in the 'news' section anyways?

[freecableguy]

This all makes sense based on the graphs above:

(all calculations done in watts, W)
7800GTX SLI - 7800 GTX = 328 - 237 = 91W (~90W per 7800GTX card)

7800GTX 512MB SLI - 7800 GTX 512 = 407 - 274 = 133W (~130W per 7800GTX 512MB card)

Additionally, this checks with the following information:

7800GTX 512MB - 7800GTX = 274 - 237 = 37W (~40W delta for 130 - 90W calculated above)

7800GTX 512MB SLI - 7800GTX SLI = 407 - 328 = 79W (about double the above delta of 37W)

So, conclusions:
a single 7800GTX card consumes 90W at full load (475Mhz and 1.4v)
a single 7800GTX 512MB card consumes 130W at full load (550W and 1.5v)

90W*(550/475)^2*(1.5/1.4) = 129W

Hmm...looks like my frequency/voltage scaling calculation looks good...thoughts?

-FCG

[freecableguy]

Ya, but 1kW is still overkill. 800 would be more than enough. Those measurements were taken from the PSU's power cord, so minus the inefficiencies of the AC/DC conversion, and you're left with maybe 350watts max draw from all the hardware components. Even if you DOUBLE that under overclocked situations, which will never happen, 700watts actual draw = 800watt PSU max.

No, a single GTX 512 will not use up 130watts by itself because the dual core CPU would be under more strain when running in SLI, adding to the delta figure.

Why is this thread in the 'news' section anyways?

My point of this post was never that you need a 1kW unit over the 850 SSI. All I was trying to get across is that 500-600W units are quickly reaching EOL for those that go with massive CPU and dual GPU overclocks.

[HiJon89]

So, if 400W is 2x 7800GTX 512MB and a 2.4Ghz 4800+ all at stock speeds...then what does this mean for GPU's running at +150Mhz core and +250Mhz (eff) memory and an FX-57 at 3.6Ghz+???

Still think 500W is off base?

Also, looks at the delta between 7800GTX 512MB to Dual cards...407-274W would suggest (although I know this is not a completely true calc) that a SINGLE 7800GTX 512MB card consumes about 130W at FULL LOAD. So my calculation based on 80W per GPU in stock form may actually be very conservative.

-FCG

I believe that 407W for Dual 7800GTX's is for the entire system, including mobo, RAM, HD, etc. So assuming you overclock everything, that would probably up the power consumption to around 550-650W. Remember, this is at absolute full load on CPU+GPU which the system will rarely experience. Even so, the 510W SLI is rated for 650W Peak and taking into account PCP&C's very conservative rating system (PSU's rated at 50C) I don't think the 510W SLI would have a problem handling it.

[freecableguy]

I believe that 407W for Dual 7800GTX's is for the entire system, including mobo, RAM, HD, etc. So assume you overclock everything, that would probably up the power consumption to around 500-550W. Taking into account PCP&C's very conservative rating system I don't think the 510W SLI would have a problem handling it.

1) PCP&C doesn't rate "conservatively," other PSU manufactures inflate their ratings. So when PCP&C says the unit will do 510W continuous thats what they mean...no more than 510W continuous (and they have overcurrent trips that will cause problems if you decide to test this).

2) You never want to operate any PSU unit over about 90% of the total duty cycle. When I get to 0.90*510W=459W I start to begin thinking about a bigger unit.

3) 500-550W of continuous power draw on a PCP&C 510 PSU will lead to problems and failure (I can prove this).

Again, my point was only that the newer 850 and 1000W units aren't as crazy as we first though (espcially when we start seeing 7800GTX SLI overclocked on a Intel 955XE chips, also highly overclocked!).

-FCG

[Cooper]

What`s the point of this thread ?
I`m sorry FCG but yr calculations look very incorrect indeed.
Also if I was at yr place I would get two decent PSUs - one for SLI, one for everything else

[mike]

I agree with FCG - while the 510W might be able to handle it - it quickly becomes a question how good and how long it will be able to handle it at close to 100% load on the PSU. I personally think it is asking for trouble - that is best avoided.

[perkam]

I'm really wondering what this has got to do with news...just trying to get the most views maybe?

Good Point.

FCG, for a story to be considered news, it needs to have a link in the first post. I've added the link for the PCP&C 1kw psu to your first post...the one here:

http://www.pcpowercooling.com/produc...php?show=TC1KW

Do let us know of you it performs...first performance numbers of a 1k psu should be news indeed

Perkam

[[XC] leviathan18]

it hink you had a bad experience with that 510w psu from pc power and cooling f you look @ the stress test from THG for psu you will see how they perform and what the ceo said about it... interesting read ....

if you look to some of the top WR you will see they dont use 1kw psu to achieve 7.5ghz in a P4 and that draws A LOT OF POWER....

from next year you wont need more than 510 or 600w for sure

[HiJon89]

1) PCP&C doesn't rate "conservatively," other PSU manufactures inflate their ratings. So when PCP&C says the unit will do 510W continuous thats what they mean...no more than 510W continuous (and they have overcurrent trips that will cause problems if you decide to test this).

PCP&C PSU's are rated at 50C, if the PSU is running at <50C, its continuous and peak power output increase, just as a PSU's continuous and peak power output will decrease as the PSU temperature increases.

3) 500-550W of continuous power draw on a PCP&C 510 PSU will lead to problems and failure (I can prove this).

I agree that running a power supply at its max for an extended period of time will damage it, but total full load is not how computers are run continuously. Maybe for a few seconds the computer will reach its maximum power draw, but that is what the peak power rating is for.

[bachus_anonym]

A64 3700+ @ 3300MHz 1.78v, 2x1GB RAM, Single 7800GTX 512MB OC @ 670/2050MHz, 1 HDD, 1 CD-ROM, 2x80mm + 2x92mm fans ---> MAX 300-320W througout 3DMark01/03/05, measured with my Kill-A-Watt meter

Same config, but with plain R7000 PCI ---> 190W during SP2004 Blend

[[KoG]^weaZel]

I can back FCG up here. I was running an OC'd 840EE and 2 6800GTs on a 510. This rig runs 24/7 crunching D2OL on four installs so 100% cpu load. The 510 was running the fan at full speed all the time even without video card load. Installed the 1k and now the system is able to run much quieter since the psu fan isn't screaming away.
When speaking with the rep from PC P&C, he said that I was running the 510 at about 80%. I had used an online psu calculator and it figured my system to be using about 585 watts.

[freecableguy]

PCP&C PSU's are rated at 50C, if the PSU is running at <50C, its continuous and peak power output increase, just as a PSU's continuous and peak power output will decrease as the PSU temperature increases.

LOL, the ratings for actual components may increase or decrease based on temperature but the internal overcurrent trip/cutoff is set based on amps drawn. Nothing changes the fact that 650W worth of amperage will cause the PSU to eventually fail...usually sooner than later when dealing with high duty cycles.

As for the argument about computers only operating at peak power during limited time...try D2OL or HL2 or Far Cry of NFS:MW and then get back to me on that one...