Evga 1070s: Why Such a Difference in Power Requirements From Card to Card?

[SPL Tech]

So Evga makes several versions of the same 1070 card. They change the cooling, lighting, looks and to some extent the overclock, but they are all more or less the same base 1070 GPU. However, the listed power requirements vary greatly from the lower end models requiring 150W to the higher end models requiring 215W. The low end models use one 8 pin connector and the higher models use two. Now I know a card with a higher clock rate will use more power and the different cooling methods might use a watt or two more compared to each other, but there is no way in heck that a ~70 Mhz. difference in core clock speed is going to account for a 75W increase in power. So why is there such a huge difference? Look at the below link for more info:

http://www.evga.com/products/product.aspx?pn=08G-P4-5171-KR

 

[EarthDog]

It's pretty normal, actually.

I'm guessing this is a function of the gpus being topped out already so in order to get higher clocks and boost, you are breaching the power envelope to do so.

 

[SPL Tech]

It's pretty normal, actually.

I'm guessing this is a function of the gpus being topped out already so in order to get higher clocks and boost, you are breaching the power envelope to do so.

Yea, but a 30% increase in power consumption for a 3% increase in clock speeds? If that was the case, the extreme overclockers who really push it would be flipping circuit breakers and these cards would be drawing 500W. That's not the case.

 

[Alaric]

Do they up the available power on the higher end cards for folks who are going cold? I thought EVGA's top tier cards were built to be suitable for huge OC on DICE and LN2. Big MHz=Big wattage. On air the top cards are probably limited by cooling to roughly the same speeds as the rest. Once the temperature headroom is increased you can feed it more power, so those cards have that power available. I'm asking as much as guessing here.

 

[EarthDog]

They aren't out of the box, no.

As far as 3% clocks and 30%. Clockspeed never scales like that with power. I'm surprised too, but it's likely using more voltage to get there, so that is also a factor...

 

[Alaric]

Ahh. I forgot the power requirements aren't linear. That would do it.

 

[SPL Tech]

Do they up the available power on the higher end cards for folks who are going cold? I thought EVGA's top tier cards were built to be suitable for huge OC on DICE and LN2. Big MHz=Big wattage. On air the top cards are probably limited by cooling to roughly the same speeds as the rest. Once the temperature headroom is increased you can feed it more power, so those cards have that power available. I'm asking as much as guessing here.

I've never found temps to be a limiting factor in overclocking any GPU made in the last few years. In every case I've encountered, the limiting factor is the maximum voltage the GPU allows to be applied. Nvidia has hard mods on how much extra voltage you can add (it's very little), and so you reach the voltage max well before the temp max. On the memory, you end up artifacting or crashing the display driver well before the memory chips overheat. As such, the temp thing should really only matter on fully unlocked cards or those with volt mods.

As far as power scaling goes, look at the 08G-P4-6274 Evga 1070 which has a clock speed of 1506 and a power requirement of 215W. Then look at the 08G-P4-6171. It has the exact same clock speed, but only a 150W power requirement. Both cards even have the exact same cooling fan setup. So a massive difference in power requirements... for what? They are almost identical cards. There goes the clock speed theory.

http://www.evga.com/products/product.aspx?pn=08G-P4-6274-KR

 

[Alaric]

Yeah, my card's listed power requirement is 150 watts, and it's far from being a slouch in the clock speed department. (2126 MHz Boost)

 

[EarthDog]

Why don't you reach out to evga and ask, SPL...

 

[Alaric]

They are almost identical cards. There goes the clock speed theory.

I was actually theorizing potential clock speeds, given proper cooling. I didn't just randomly throw stuff out there.

 

[SPL Tech]

Why don't you reach out to evga and ask, SPL...

I finally did. They said the higher power cards have a 10+2 power phase while the lower ones have a 4+1. Not sure how that equals an extra 75W though.

 

[EarthDog]

Me either....

 

[wingman99]

I think there just advertising the Maximum power the card can draw with overclocking. It says on the EVGA site "Max Power Draw" http://www.evga.com/products/product.aspx?pn=08G-P4-6274-KR

 

[Woomack]

Better power section almost always means higher TDP in specs regardless of brand. All these EVGA cards at higher power draw have 2x(+) stronger power section. It's the same with other brands. In theory TDP should be without big changes but they probably specify max power draw / theoretical power limit of the card like wingman said. Max wattage is limited by BIOS as it should be 375W on 2x8pin so it's much more than specified max power draw. It looks like there is huge headroom made with overclocking on mind. And these cards are not even designed for LN2 benching so I'm not sure why they made it considering power limits and low voltage adjustments.

 

[wingman99]

I wonder if it is a power section change 170W 4+1 phase 150w 4+1 phase.

 

[Woomack]

In most reviews max power draw of stock GTX1070 was 180-200W even though TDP was 150-170W. 170W versions have probably higher voltage range and higher power limit set in BIOS. At stock have 88MHz more so it's probably that 20W difference. Still it's just theoretical value as real wattage is probably higher.

 

[wingman99]

My GTX 1070 and CPU from the wall is only ~250w 80% efficiency with the PSU = 200 actual watts being used by my Rig.

 

[EarthDog]

What psu do you have that's only 80% efficient? Sounds very old or cheap..

 

[wingman99]

What psu do you have that's only 80% efficient? Sounds very old or cheap..

Corsair HX620, I purchased it 03/10/08 so the 5 year warranty is way over and it still works great. I'm going to runn the HX620 untill it dies.

 

[Woomack]

I have HX850 from about the same time. If I'm right then real efficiency is higher. My HX850 was relabelled from 80+ Silver to 80+ Gold about half year after I purchased it and inside was exactly the same. In some reviews had ~92%+ efficiency. Btw. about 3 years ago I had water leak and water was dropping into this PSU. PSU only shut down, I dried it and was working again without issues. There are stains inside as water was dyed.