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Would it be possible to use 3 molex splitters to power 2 6 pci cables

Last response: in Graphics & Displays
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November 16, 2012 11:12:11 PM

hey im considering buying a new graphics card to replace my old amd 5450 with an MSI GeForce GTX 560Ti-448 1280MB GDDR5 PCI-Express Graphics Card.

But my power supply doesn't have 2 6 pin pci power cables to power it and i was wondering if it were possible to connect 3 molex splitters in series from my one spare molex output, then connect 2 molex to 6 pin adapters.

Would this be a safe solution ?
If not then what steps could be taken to create a solution ?

Power supply : 500w
Cpu : Amd FX - 4170
Graphics card (current card) : Amd Radeon 5450
8 X USB Ports
1 X PCI X 16 slot
1 X 1tb HDD
1 X CD/ DVD RW Drive
2 X DDR 3 slots
4 X Fans
November 16, 2012 11:19:16 PM

depends on your 12 volt rails and how many amps they can pump through im guessing its a cheap psu not having the pcie plugs to be honest you need to go get a decent power supply otherwise you risk damaging all your new gear. and if it is a cheap psu it would bet my house it cant put out 500watts either go spend 60 bucks or so and get a decent entry level 80+ psu from the likes of antec/corsair/seasonic around 500watts then you will be fine
a b U Graphics card
November 16, 2012 11:31:13 PM

Your card should have come with 2 dual-molex to 6-pin PCIe adapters. Three is too little to run safely, but it can be done. First off, could you tell us your exact PSU model, as this will help determine how much power the 12v rail can provide. High end PSUs can provide almost the entire rated supply on the rail, while others fry themselves.

What they provide is the MINIMUM RECOMMENDED power delivery method, not the best possible. Try and see if you have at least the 4 molex plugs, because less adapters=better and safer performance.

On a side note, I helped a guy out once who wanted to split a single 6-pin into two 6-pin PCIe plugs (6-pin PCIe is rated for 75W, 8-pin PCIe is rated for 150W), and his GTX 460 works fine, but, like I said, it's not recommended.

Remember this, if you put so many adapters in, you decrease the total amount of power each plug can deliver, although your PSU may be up to spec. 150/2=75 each, and then dividing that again will put an enourmous strain on your PSU. If I were you, I wouldn't risk it (although it may work), and buy a new PSU.
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a b U Graphics card
November 17, 2012 12:05:04 AM

The reason that two molex connections are combined to a single 6pin is not total load on the PSU, its the amps that go through each wire in the connector. People have no problem at all with bridging in a bunch of molex to 6pin adapters as long as they use two molex to each 6pin. (and as long as the PSU power rating supports the load being driven).

If you start putting a single molex to a 6-pin it will work electrically, it just puts 2X the amps through the connector -- that's still safe but above the design limit. I happily use dual molex to 6pin in two PCs, but would not use a single molex --> 6 pin adapter.

What you are suggesting is putting the entire load of two 6pin connectors through a single molex. This is 150W or 4X the design current, and potentially more than 10Amps. That connection can get hot. If the connection has a bad spot (slight build fail, some dirt or corrosion preventing good contact) that connection can get really hot. This is not a good idea. (note: the GTX 560Ti-448 is rated around 210W so is really pulling power through those connectors, they are not there for show. Assuming a full 75W through the PCIe slot that still leaves 135 through the two 6-pins before you add in an OC related load)

Jasont76 is right. Do post the brand of your 500 watt PSU, there are some problem units out there that literally burn up when pushed. Do recognize that not having enough output wires on a 500w PSU is a sign that the PSU is not a good one. Do swap for something like an Antec vp-450 @$40 or better.
November 17, 2012 10:12:02 AM

this probably next to no use to you but i have checked my psu and it says it is a ROHS psu and i have never heard the brand before and there was no model number that i could see.

could you recommend a good quality psu on a budget up to £80 (i am willing to part with more if necessary)
November 17, 2012 10:47:32 AM

Here's a link to a 500 watt PSU:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

consider getting a modular power supply so you only have to install the cords that you actually need. I have a corsair ax750 professional series, which i would recommend if you are planning to do any upgrading, I got it for $149 (117 - 110 euros), at fry's (a local electronics store), though you may have to do some shopping.
November 17, 2012 11:05:04 AM

the power supply looks like what i am looking for and i found it in 600W do you know if there is a 700 or 750 watt version ?
November 17, 2012 11:06:05 AM

also what would your views on this power supply be ?
November 17, 2012 7:39:43 PM

t1mone said:
the power supply looks like what i am looking for and i found it in 600W do you know if there is a 700 or 750 watt version ?

unless your planning sli 500-550watt is plenty cpus and all the rest of your gear consumes less and less power each generation there is no need for more power
a b U Graphics card
November 18, 2012 12:01:05 AM

Agree that 500W should be enough, and that each generation parts are using less power, however your choices of processsor and video card use a ton of power.

GTX 560Ti-448 = Over 200W for the card. Without overclock.

Your CPU is not the most efficient either "At idle, the FX-4170-based machine uses almost 20 W more than the Core i3-3220-based box. Under load, that gap grows to a staggering 103 W. The dual-module FX almost doubles the consumption of a quad-core Core i5, in fact. " http://www.tomshardware.com/reviews/fx-4170-core-i3-322...

Given AMDs tend to OC well, and tend to consume massive amounts of power when OC'd, If you plan to OC your AMD processors and your video card then step up to 600-650. Otherwise a 500W should be enough. (A 460W PSU supports my older 200W gtx260 and power pig i7-920 just fine, but I only mildly OC the gpu and do not OC the cpu).
November 18, 2012 11:41:44 AM

ah right but either way i would still have to purchase a new power source as my current one has no spare molex cables to power the new graphics card so i would probably need a new one with the correct cables with 6 pin connectors but also i am looking to upgrade my pc in the future so i was thinking of getting a bigger power supply so i won't have to buy a new one after that to compensate
a c 79 U Graphics card
November 18, 2012 1:44:21 PM

t1mone said:
this probably next to no use to you but i have checked my psu and it says it is a ROHS psu and i have never heard the brand before and there was no model number that i could see.

RoHS is an European Union directive 'The Restriction of the use of certain Hazardous Substances in Electrical and Electronic Equipment', basically it means there's no lead in the solder used in the unit. (also the use of Mercury (Hg), Cadmium (Cd), Hexavalent chromium (Cr6+), Polybrominated biphenyls (PBB) and Polybrominated diphenyl ether (PBDE) is forbidden as well)

a c 79 U Graphics card
November 18, 2012 1:53:54 PM

http://www.overclockers.co.uk/showproduct.php?prodid=CA...
Corsair Enthusiast Series TX750M High Performance 750W '80 Plus Bronze' Modular Power Supply £89.99 inc VAT

Should be plenty, even for a 'modest' dual gpu system with cards that are NOT rated at 300 watts each
November 18, 2012 4:53:32 PM

sounds good and this may be a bit of a silly question would the fan be pointed up or down as if its facing down it would be blowing air directly onto my air cooled cpu could it damage it ?
a c 271 U Graphics card
November 18, 2012 5:04:04 PM

Kari said:
RoHS is an European Union directive 'The Restriction of the use of certain Hazardous Substances in Electrical and Electronic Equipment', basically it means there's no lead in the solder used in the unit. (also the use of Mercury (Hg), Cadmium (Cd), Hexavalent chromium (Cr6+), Polybrominated biphenyls (PBB) and Polybrominated diphenyl ether (PBDE) is forbidden as well)

Yeah, bloody killjoys! I still have a good 1/4 pound of lead solder knocking about though which I like to use when working in a confined space so up yours HSE! :finger:
a c 79 U Graphics card
November 18, 2012 9:15:17 PM

t1mone said:
sounds good and this may be a bit of a silly question would the fan be pointed up or down as if its facing down it would be blowing air directly onto my air cooled cpu could it damage it ?

the fan blows into the power supply, there is a honeycomb-style vent on the back of the psu (not visible on the pic) that exhausts the warm air out of the case. So it doesnt really matter which way the psu is installed, some cases have it at the top and others at the bottom facing which ever way, it'll always blow out of the case.


@MM
They are only thinking whats good for you. :lol: 
a c 271 U Graphics card
November 18, 2012 9:22:17 PM

Kari said:
@MM
They are only thinking whats good for you. :lol: 

A bit of lead poisoning never hurt nobody, I don't need their protection. :whistle: 
!