Run 2 GPUs (1070) on the CX550m?

Christopher Aubert · Nov 2, 2017

I understand that there's only one PCI connector cable (that has two 8-pin connectors), but can you use the same cable and connect one of the 8-pins to one of the 1070s and the other 8-pin to the other 1070? Would it work like that?
Edit: Typo in the title, PSU is the CX550m, NOT the 500m.

jankerson · Nov 2, 2017

Don't even try it.

You need to get a new PSU.

I recommend a Corsair TX650M, Seasonic Focus 650W or Seasonic G-650W.

maxalge · Nov 2, 2017

Christopher Aubert :

that psu is really not good enough, barely able to run a single 1070

Christopher Aubert · Nov 2, 2017

maxalge :

Sorry, there was a typo in the title, PSU is actually the 550w. Would you still say the same?
Also, the idea that the CX500w barely being able to run the 1070 is... simply not true. Like how are you figuring that?

samer.forums · Nov 2, 2017

Yes you can connect them but two GTX 1070 using 550 watts will make the power supply run at 90%

Total system power gaming with one GTX 1070 is 310 watts (Anandtech review)

Another Card will add 150-180 watts , will be ~490 watts ..

will work but will be on the edge of the powersupply

CX550M (2015) can deliver 550watts on 12V it is very capable power supply

Make sure it is the 2015 model

bjornl · Nov 2, 2017

Christopher Aubert :

Short version is no.
It "might" technically be possible to do so in an ideal environment with ideal temps in the room and so on. But that is not how you want to run a PC. You would be a dust clump or adding a new disk away from "oh oh".

This would raise the temps in the case quite a lot. As the temps rise, you would be pushing your PSU closer and closer to the limit because PSU efficiency drops as temps rise. Meaning for this to work, you would need to be in a cool room with a good hepa air-filter and hard-surface floors (low dust). And you would need a very large case with just exceptional airflow.

It this risk really worth it to you? Why not sell the 1070 and buy a 1070ti or 1080? This would have better game support, simpler cooling and not require a new PSU.

maxalge · Nov 2, 2017

Christopher Aubert :

because you still have the rest of your system to power, you want to be at ~80% or less of max rated wattage for longevity and stability

for sli 1070 you want at least 650w

jankerson · Nov 2, 2017

maxalge :

Christopher Aubert :

because you still have the rest of your system to power, you want to be at ~80% or less of max rated wattage for longevity and stability

for sli 1070 you want at least 650w

Let him try it with that budget PSU.... LOL

Since he is doubting us..

$800 in graphics cards.....

samer.forums · Nov 3, 2017

maxalge :

Christopher Aubert :

because you still have the rest of your system to power, you want to be at ~80% or less of max rated wattage for longevity and stability

for sli 1070 you want at least 650w

you said that power supply can barely run single gtx 1070 , and not SLI ,this is very wrong.

a Full System with GTX 1070 in all reviews will draw 300-310 watts .. the whole system. go and check reviews to be convinced.

samer.forums · Nov 3, 2017

jankerson :

He can doubt you , your way of thinking is the price of the PC not calculating the power nor looking at the quality of that power supply (which is good)

This is not scientific , and just plainly guessing.

That power supply is budget , yes , but it is a GOOD budget power supply.

he can even run a $100000 card on it , the price of the card has nothing to do with power.

and dont laugh at OP it is against the Rules here.

jankerson · Nov 3, 2017

samer.forums :

jankerson :

He can doubt you , your way of thinking is the price of the PC not calculating the power nor looking at the quality of that power supply (which is good)

This is not scientific , and just plainly guessing.

That power supply is budget , yes , but it is a GOOD budget power supply.

he can even run a $100000 card on it , the price of the card has nothing to do with power.

and dont laugh at OP it is against the Rules here.

Well he can call you when his PSU burns up or it just doesn't work for very long etc.

I ran the numbers... BEFORE I POSTED.... The 1st time.... When I recommended a 650W PSU.

He needs at least a 650W Quality PSU for a GTX 1070 SLI setup.

Bottom line is he will have problems.

samer.forums · Nov 3, 2017

jankerson :

it will not burn nor explode . but will be 90% load when he games . will get hot , thats all . and you ran nothing , no numbers at all. as I said , 310 watts for the whole system , Add 150-180 for another card , 490 watts max.

his power supply can deliver 550 watts FULL , ts a DC to DC power supply can deliver 550watts on 12 volts

and you said you ran numbers ? give me the numbers ?

you said bad power supply for it ? I doubt you looked at corsair site at all , nor read the specs of that power supply and that it has 5 years warranty . NOR seen it was released for $114 but now after 3 years it is selling for $60

NOR seen any reviews about it , which I can show you.

you give ALL your advice from guessing . and looking at the prices , if it is low price then it is bad .

you show no proof what so ever.

here is the power supply (notice the original list price $114

http://www.corsair.com/en-us/cx-series-cx550m-550-watt-80-plus-bronze-certified-modular-atx-psu-na

yes it is better he gets a 600-650 power supply , but to say that his power supply will BURN and not work ?

This is simply WRONG.

good Power supplies are made to work within 100% load under warranty. actually PEAK is more than 550 watts.

jankerson · Nov 3, 2017

Like I said he can call YOU when he has problems.... And he will.

samer.forums · Nov 3, 2017

jankerson :

No he will not. it will run fine , but will run hot and full speed fan when he games.

All what he will experience is noisy Fan from the powersupply .

Kasper Jorgensen · Nov 3, 2017

samer.forums :

You are making the assumption that OP has the exact same system as a review. OP didn't tell anything about his system so we need to consider worst case. A GTX 1070 will be at 150W yes, but only for the reference cards. A 3rd party overclocked card will draw more power and some of them can get close to 200W.
With that said, and assuming his system will draw 490-500W like you assume, it is very close to the limit of that PSU. If you check the specs it is only rated at 40 C, which at 90% load, it could easily get hotter than 40 C and above that temp it can no longer supply 550W. High quality PSUs is rated for 50 C and overall has better cooling with better fans. They also have caps rated at a higher temp.
In the end, the CX550 is a decent PSU for a low or medium end build. But it is definitely not the choice for SLI or overclocking. A medium quality PSU like the CX series should not be pushed to the limits.

samer.forums · Nov 3, 2017

Kasper Jorgensen :

read the reviews , the full system reviews power all have overclocked CPU and SSD and Harddisk and fans. and they range from 270 to 310 watts full load ... check the reviews.. Anadtech even got 310 watts using overclocked 140 watts CPU (the E CPU)

there is nothing called decent for medium build ... there is wattage calculation. and volt stability ...

The OP did not ask if his power is enough or not.

He Asked if his PCIE power cable can be used or not . one cable with two 8 pins plugs.

The Answer is yes.

Why do you assume that he cant calculate his system watt all of you ?

This is all off topic. and he as I can see left the thread altogether from the replies off topic here and assuming he does not know how to calculate watt. I am 100% sure he is not coming back.

Most people here in Tomshardware assume people are idiots when they answer their questions.

Kasper Jorgensen · Nov 3, 2017

There is certainly something called a decent PSU for a medium build. The CX series is a decent PSU but no way a high quality one.

There is way more to a PSU than just wattage and Volt stability. Like i said there is rated temp and quality of the components inside the PSU, none of which the CX series will shine. You should really never load a PSU more than 80% but this goes specially for the lower quality units.

BTW. This is not off topic, he did ask about a cable yes, but people are advising him to get a better PSU if he likes to run SLI. With that said, he will probably get more performance in most games by getting a single GTX 1080 instead, in which case he can keep his current PSU.

Run 2 GPUs (1070) on the CX550m?

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