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[Tracer76]

lol my PSU is in tier 5 a 630 watt raidmax i got a while back for 75 dollars

Raidmax good mid range cases, but very bad ripple effect off the +12v rail which is not a good thing when it comes to a PSU.

[wooDy]

senior electrical engineering student here.  overclocking is a delicate balance between voltage and di-electric breakdown and between current and heat.  from the article you linked, those numbers are "Videocard Power Consumption (Total System Power Draw)"

proves my point, perfectly.  630watts TOTAL power draw (though they do not specify at the wall or at the power supply.  i'll assume power supply for worst case scenario) for an x2 crossfire system (4 gpu). 

amd's new 4890 are a respin on a mature manufacturing tech.  they will not use that much more power (maybe 10 - 15% more). oh, look here:
http://www.tomshardware.com/reviews/radeon-hd-4890,2262-13.html
not quite 10% more power under full load.

oh, look again at that review.  their test system is an intel core i7 EXTREME processor (140 tdp) and x58 chipset.  using the hd 4870 x2 card, maximum power draw is ONLY 418 watts AT THE WALL.  that means counting power supply inefficiency. 

[Tracer76]

Jorsh So what PSU do you have you never mentioned at all. All you said was


" run an OC'ed 4870 w/ no problems on a 380 watt PSU....  Woody will tell you those psu req's are retarded..."

Which is a Antec EarthWatts at 380 which is not a bad PSU for the basics. Actually some cards out there higher end ones like the 4870, GTX260 216 core ect have been known to power spike on 3D apps over 1,000 Watts. Also the 4870 not a bad card just bad design when it has some voltage regulator issues as well with Furmark..

[wooDy]

Actually some cards out there higher end ones like the 4870, GTX260 216 core ect have been known to power spike on 3D apps over 1,000 Watts. Also the 4870 not a bad card just bad design when it has some voltage regulator issues as well with Furmark..

spiking over 1000 watts?  um, spiking 1000 watts through the 12v line (let's even assume a 100 watts through the various 5v and 3.3v lines), so for 900 watts, you get a current of 75 amps.  you will likely heat through your wire shielding and cause a short (not to mention drop the line voltage far enough below 12v to cause the card to crash).

most pcie cables are 18 awg.  let's just assume that they are really 16awg.  the AWG industry standard recommends NO MORE than 3.7 amps for power transmission.  see a problem?  you will likely generate so much heat you burn through your wire shielding and cause a short, or at best, the 12v line will drop below atx specs and crash the card.

[Tracer76]

Actually some cards out there higher end ones like the 4870, GTX260 216 core ect have been known to power spike on 3D apps over 1,000 Watts. Also the 4870 not a bad card just bad design when it has some voltage regulator issues as well with Furmark..

spiking over 1000 watts?  um, spiking 1000 watts through the 12v line (let's even assume a 100 watts through the various 5v and 3.3v lines), so for 900 watts, you get a current of 75 amps. 

most pcie cables are 18 awg.  let's just assume that they are really 16awg.  the AWG industry standard recommends NO MORE than 3.7 amps for power transmission.  see a problem?

There was a article on this issue and power regulation on new cards a while back. I know that www.hardwarecanucks.com did the article at the time and still trying to find it. But it was showing that they saw spikes on a 4870 over 1000W for brief periods of time less than a second but could fry a PSU especially a tier 5.  Trying to find that one again.

[Jorsh]

yeah, its an earthwatts 380.