Powering a GTX 980ti in a CMP

[gsloan]

I've got an eVGA 980ti FTW in my system, running overclocked +50MHz. I use a 3rd party tool for fan control (forget its name) - at any rate, with 4 HDDs, 3 SSDs, and a USB card.

While my old MVC GTX 780 would cause the system to hard shut down when running eVGA's scanner tool after 5 seconds, I've run the same tool successfully for over 4 hours with the flashed 980ti powered off of the motherboard connectors. I didn't think it'd work that well, given the supposedly similar power consumption between the two, but the 980ti FTW even with a 6 and 8 pin seems perfectly happy in my 4.1->5.1 system.

Just my own experience.

 

[TzunamiOSX]

I am wondering how close to the edge my system is so I actually took the time to do the math. Well, "quick math" since I couldn't find some of the numbers so their is some very quick guess work based on a little info (I figure the numbers below are within 10-15% of being accurate):

Dual Hex 3.3 CPUs, Ram, Motherboard 300 (total guess based on other numbers I found)
GTX980Ti 250
SSD 30
PCI Single SSD 40 (I'm not sure how many watts the actual PCI card gets so I added a bit)
PCI Double SSD 75 (I'm not sure how many watts the actual PCI card gets so I added a bit)
Cool Spinning 4TB HD 10
Cool Spinning 4TB HD 10
7200 HD 12
7200 HD 12
Superdrive 50 (couldn't find any data on this so this is a total guess)


My system total 789

Total cMP power supply watts 980

So i have 200 watts extra more or less depending on my guesses above. I can live with that. Anyone have a better guess on the numbers above?

Some numbers are wrong!

The TDP (150) is not the needed power of the CPU. The CPU is working with around 1,18 V and 82 Ampere under full load. So you get 96,76 Watt for one CPU and not 150

System total on full load is around 100 Watt lower.

TDP (thermal disign power) is important for the dimension of the cooling system.

 

[ifraaank]

I use the 980Ti ACX 2.0 NON-SC and that works beautifully.

 

[itdk92]

What external PSU would you use to power 2x 980TI ? How do you manage with the power cables that go to the card itself in the case - aka, where do they get "out" to the PSU?

 

[deppest]

After the initial hickups the GTX 980ti SC ACX2.0 has now been running without any issues for about a month. Its 6pin is connected to two HD bays and the 8pin to the onboard 6pin. Attached snapshot shows the power draw under furmark. GPU CUDA rendering draws substantially less power.

 

[h9826790]

After the initial hickups the GTX 980ti SC ACX2.0 has now been running without any issues for about a month. Its 6pin is connected to two HD bays and the 8pin to the onboard 6pin. Attached snapshot shows the power draw under furmark. GPU CUDA rendering draws substantially less power.

You better use 2x 6pin -> 8pin. Now, your Boost A doing nothing but the Boost B way over 75W limit. That 7.99A is the display limit, your card actually draw more than that. Since your Boost A is avail, it's better not to over stress the Boost B.

 

[deppest]

You better use 2x 6pin -> 8pin. Now, your Boost A doing nothing but the Boost B way over 75W limit. That 7.99A is the display limit, your card actually draw more than that. Since your Boost A is avail, it's better not to over stress the Boost B.

In the end I opted for the Pixlas mod, with the card now being connected via 8pin to the PSU directly and via 6pin to the existing mini 6pin connector. Many thanks to the forum members who have shared their insights!