HD 5970 Power vs Temp

[z3d.]

Hello!

I have as psu an Enermax Modu 87+ 700W which have 3x +12V rail, each one able to generate (that's the right word? sorry for my english) 25A for a total of 58A on all the rails together.

Considering that the maximum wattage per one rail would be something less than 300W, that the TDP of Ati 5970 is 300W and the fact that I'd like to run it at least at 1000@cpu, here we come on the Topic title:

"Someone made in the past or can make some tests about the Power that this card needs relationed to its Temperature?"

Something like this, to make it more understandable (in this case for GTX 480):



That would be extremely useful for me, in order to know if OCing this card on liquid cooling setup it will needs really 300W or maybe less power, due to power draw/heat relationship and that's all about to know if I can run safely the card OCed on only one rail of my psu or on two.

Thank you for your advices

[sfield]

A few points:

1. Some power supplies claim to have multiple 12v rails, when they really have one big rail. Not sure if your power supply is such a unit -- search for posts/articles on this.
2. 25amps * 12volts = 300W. If your power supply isn't a single 12v rail, and you want to exceed 300W power draw, you can combine PCIe power connectors (the 8pin variant) from two rails. There are PCIe power combiner cables available that do this.
3. For your purposes, you really want a frequency to power consumption chart. Watercooling doesn't change the power consumption of the cooled component, it reduces the temperatures (and overall noise, in the case of the 5970).
4. I have 2 5970s, both water-cooled. Early on, I tried air-cooling, but you really have to crank the fan speed (and noise) up beyond core clocks of about 825. One big limiting factor with the 5970 and aircooling is the VRM temperatures (throttling is triggered around 120C). I'm running my cards at 950/1200. I think with furmark, the cards are pulling close to 400W at this clock. My cards can also run stable at 1000/1200, but power draw goes up quite a bit (I don't remember how much).

Hello!

I have as psu an Enermax Modu 87+ 700W which have 3x +12V rail, each one able to generate (that's the right word? sorry for my english) 25A for a total of 58A on all the rails together.

Considering that the maximum wattage per one rail would be something less than 300W, that the TDP of Ati 5970 is 300W and the fact that I'd like to run it at least at 1000@cpu, here we come on the Topic title:

That would be extremely useful for me, in order to know if OCing this card on liquid cooling setup it will needs really 300W or maybe less power, due to power draw/heat relationship and that's all about to know if I can run safely the card OCed on only one rail of my psu or on two.

Thank you for your advices

[z3d.]

Hello and thanks for your reply

Well, about the Temperature versus Power consumption, did you noticed this tread? http://www.xtremesystems.org/forums/...d.php?t=252779

That's why I'm thinking that the same thing could easily happen with a 5970, don't you think so?

[sfield]

I hadn't seen that thread before, but it appears to call out component operating temperature efficiency differences. It's possible this is applicable to the 5970, to what degree is unknown. I doubt this would overcome the 300W limit you're worried about when running at 1000 gpu clock -- the observed improvement margin looks fairly narrow.

With a 5970, I think you'll be pulling ~350-400W under maximum furmark load at 1000 gpu clock, watercooled. I'll try this later in the week and let you know what power consumption I observe (at 950, 1000).

Hello and thanks for your reply

Well, about the Temperature versus Power consumption, did you noticed this tread? http://www.xtremesystems.org/forums/...d.php?t=252779

That's why I'm thinking that the same thing could easily happen with a 5970, don't you think so?