Radeon HD 7950 Power consumption - Stock and OC - Single and CFX

[Face2Face]

My 7950 is a pig.... I didn't think a single 7950 could draw this much wattage being heavily overclocked.

My desktop idle wattage

Taking 85% efficiency into consideration the PC uses about 64 watts. I have all the power saving features still enabled in the bios.

3570K @ 4.8 and the 7950 @ stock speeds 880/1250 - 1.093v power limit 0% running the Valley benchmark @ Extreme HD settings.

After 85% - 207 watts



3570K @ 4.8 and the 7950 @ 1300/1650 - 1.235v with power limt set to + 20% Running Valley in Extreme HD

After 85% = 440 watts D:




Playing Crysis 3 @ 4.8 and the 7950 @ 1250/1650 - 1.2v with power limit set to + 20%

After 85% = 413 watts

The efficiency could be off by a couple of points, still this is a lot of consumption. Not sure if being on a 7970 PCB also allowing me to draw more current? I will retest this when me second 7950 gets here, I will be using a 750 watt PSU with the extra card.

 

[BallaTheFeared]

You're going crossfire??

 

[Silverforce11]

Don't forget, your CPU is heavily OC as well, when you unleash the 7950 and get a 50% performance gain, you are pushing the CPU much more than it at stock, thus the entire system power use goes way up. The difference is not all to the GPU, its the entire rig running faster.

 

[Face2Face]

You're going crossfire??

Yes, I think I need to pull another 15a circuit to my office
I have been looking for another card for a while and have been very picky in my search. I finally found one that should be equal to the one I have, I hope at least. 89% ASIC / 7970 PCB and purchased late 2012. I know it does 1150 @ 1.15V and the memory does 1700 @ 1.6v.

 

[Face2Face]

Don't forget, your CPU is heavily OC as well, when you unleash the 7950 and get a 50% performance gain, you are pushing the CPU much more than it at stock, thus the entire system power use goes way up. The difference is not all to the GPU, its the entire rig running faster.

Good point.

Here is my power consumption running Intel Burn test @ Maximum. No Gpu usage

 

[chimaxi83]

Heh, yeah I can easily break 1100w with my OC 3770K and two cards, also overclocked and overvolted.

 

[Face2Face]

I watched this guys video running his 3770K @ 4.6Ghz and his crossfired 7950's @ 1100/1350 and power consumption is about equal to mine playing Crysis 3. Has a gold rated PSU, but that's still pretty close.

http://www.youtube.com/watch?v=c1feSBq3o_w

http://foxvalleypcgeek.com/blog/2013/03/30/3770k-7950-crossfire-wall-socket-power-draw/

 

[BallaTheFeared]

Highest I've seen is 610 at the wall on a gold hx850 during 3dmark11

 

[Face2Face]

Highest I've seen is 610 at the wall on a gold hx850 during 3dmark11

I assume both of your cards were heavily overclocked 1200+?

 

[Termie]

This is pretty interesting.

I'd say the OP's 7950 is clearly exceeding the limits of PCIe power when it hits 518W, in a bench that requires very little CPU power. Any thoughts on the ramifications?

He has a maximum 225W available to him via the motherboard and auxiliary power 6-pin connectors. I'd guess he's at 300W in that Valley run. He might even be exceeding that limit in Crysis 3. The calculus changes if he has an 8-pin on his board, but I don't think any 7950 does, other than the Vapor-X.

 

[BallaTheFeared]

I assume both of your cards were heavily overclocked 1200+?

1200\1600 i5 @ 5Ghz

My idle is about 20w lower than yours though.

 

[stahlhart]

You forgot to add drama with an undersized power cord:

http://forums.anandtech.com/showthread.php?t=2155020

 

[Face2Face]

This is pretty interesting.

I'd say the OP's 7950 is clearly exceeding the limits of PCIe power when it hits 518W, in a bench that requires very little CPU power. Any thoughts on the ramifications?

He has a maximum 225W available to him via the motherboard and auxiliary power 6-pin connectors. I'd guess he's at 300W in that Valley run. He might even be exceeding that limit in Crysis 3. The calculus changes if he has an 8-pin on his board, but I don't think any 7950 does, other than the Vapor-X.

It's actually around 440 watts when you add PSU efficiency into the mix. But yes, my 7950 is on a 7970 PCB, which has a 8+6 pin configuration.

If you look at the PCB on my 7950 with the 7970 PCB you see one more choke and mosfet. Which I think is kinda weird.. not sure if it adds anything beneficial or not?

Reference 7970 PCB

Also, while the PEG connectors are ATX specified to do (6 pin) 75w and (8pin)150w, they actually can pull more if needed. Mostly the 6pin. Going from 6 to 8 pin, you are just adding two grounds wires and keeping the same three 12v wires.

1200\1600 i5 @ 5Ghz

My idle is about 20w lower than yours though.

Nice :thumbsup: Gotta love that Haswell. I do also have 6 120mm fans and one 230mm fan going at idle as well. Not sure how much that adds to the mix?

 

[Sohaltang]

I see about 550-600 on 2 7950's on my rig listed below. 8+6 TFIII's 7970 pcb

 

[Face2Face]

I see about 550-600 on 2 7950's on my rig listed below. 8+6 TFIII's 7970 pcb

Are those overclocked to 1150/1600? What kind of PSU do you have?

 

[Sohaltang]

Are those overclocked to 1150/1600? What kind of PSU do you have?

Thats bumping the specs to max catalyst OC. + 20 @1100/1575. Corsair 750M. You can look at some of the bench threads to see my benches at those clocks.


Using Trixx I get worse scores and cant seem to clock much higher. I know there is something Im not doing right. I tried afterburner but the new version is locked down

 

[Smartazz]

I'm surprised your power consumption is so high. With my 7950 1150/1400 1.2 volts +20 and a 1.36 volt 4.6GHz 2500K draws 360W while gaming. Idle is 95W.

 

[Face2Face]

I'm surprised your power consumption is so high. With my 7950 1150/1400 1.2 volts +20 and a 1.36 volt 4.6GHz 2500K draws 360W while gaming. Idle is 95W.

I'm guessing it's because of the high clocks and the fact that I am on a 7970 PCB. Able to draw more wattage at full load.

 

[Stuka87]

On my rig in my sig I have hit as high as ~450W with CPU and GPU pegged. And my CPU is very power hungry.

I bet if you lowered your card down to 1100MHz, the power usage would drop significantly.

 

[Face2Face]

On my rig in my sig I have hit as high as ~450W with CPU and GPU pegged. And my CPU is very power hungry.

I bet if you lowered your card down to 1100MHz, the power usage would drop significantly.

True enough. Going from stock 880/1250 to 1300/1650 pulled an additional 233 watts from the PSU when benching Valley. The CPU usage in valley is very low, so there not much going on there.

 

[Face2Face]

So I finally got PC back together after being in parts for awhile. Ran the Valley benchmark again because it seems to really stress the gpu's and get them both @ 99%

Both MSI TF3 7950's at stock clocks 880/1250 with 1.093v core and 1.6v on the memory 0% Power Limit

Max draw of 457w at the wall - = 388w after 85% efficiency.

Raised the clocks to 1150/1650 with 1.150v and a Power Limit of 20% on both cards
Max draw of 693w at the wall = 589w used by the PSU.

Jumped the clocks to 1200/1700 with 1.188v and a power limit of 20% on both cards
Max draw 827w at the wall = 702w used by the PSU.

I haven't seen any other 7950's consume this much power, I am pretty sure with these cards being on the 7970 PCB, they also have the ability to draw the same amount of power as the 7970's. Which may help these cards clock so high. The new card seems to wanna go very high as well, I just cannot keep it cool enough. Pretty sure under water both of these cards could be game stable @ 1300/1800, not happening on air.
I am also reaching the upper limits of my no frills PSU as well. After playing some games with crossfire enabled, even at 1000//1450 on both cards the difference is pretty awesome. Crysis 3 plays great on VHQ and so does Skryim. Very happy I made the move to CFX. Next up some better cooling for the stock card.

 

[monkeydelmagico]

So much for die shrinks and power saving. Makes my overclocking heart all warm and fuzzy though. Some 7950 cards are a budget tweakers dream come true.

How are you going to push higher with a 750 watt PSU?

 

[Fastx]

Nice post/info F2F and good to hear your happy with making the move to 7950 CF.

 

[Smartazz]

Is crossfire that much better now? When I tried it, it stuttered pretty badly.

 

[Face2Face]

So much for die shrinks and power saving. Makes my overclocking heart all warm and fuzzy though. Some 7950 cards are a budget tweakers dream come true.

How are you going to push higher with a 750 watt PSU?

Not gonna happen for running benchmarks at high clocks. Gonna have to wait for some more play funds for that to happen..... Should be fine for gaming at moderate clocks though. Now I have to focus on getting a better cooler for the other card so I can enjoy the silence, not the loud whine of a TF3 cooler @ 70%

Nice post/info F2F and good to hear your happy with making the move to 7950 CF.

Thanks! Very happy!

Is crossfire that much better now? When I tried it, it stuttered pretty badly.

The games I played thus far - Bioshock, Crysis 3, Metro LL all play great, not stuttering that I noticed. Even Skyrim which is a DX9 game plays great, no stutter here.... I didn't think Skyrim would benefit from CFX much, but it has, even with an ENB and 4K textures it runs amazing.

EDIT: Take that back, Skyrim is now starting to stutter.....ugh