Stupid Power supply questions

[DietDrThunder]

A bit of history first:

I purchased a COOLER MASTER Silent Pro M700 RS-700-AMBA-D3 700W ATX12V V2.3 SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Modular Active PFC Power Supply back in May of 2010 and it has been working great.

I also purchased two SAPPHIRE Radeon HD 7970 DirectX 11 100351SR 3GB 384-Bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card OC with Boost (one for my PC and one for my kids PC) back in November of 2012.

My kid no longer needs the PC and I thought, why waste a graphics card, why not have both in my PC and CrossFire the video cards. When I look at the power supply https://www.newegg.com/Product/Product.aspx?Item=N82E16817171037, it has only 2 x 6+2-Pin PCI Express output ports/connectors.

My question are these:

1) Are there any cables that I can buy that will split the 6+2-Pin PCI Express output ports to allow me to run power to both video cards?

2) Or do I need to purchase a different power supply that has 4 x 6+2-Pin PCI Express output ports?

 

[UsandThem]

That PSU is soon to be 8 years old. Since you want to run two video cards, I'd personally buy a new PSU. As they age, they lose some of their output power, and that unit came with a 5 year warranty. You easily got your money's worth out of it.

You have two sides when it comes to replacing a PSU before it dies. Some will say if it works, it's stupid to buy a new one, and use it until it shows issues or dies. The other side will say it's had a good run, capacitors age from heat and time, so it makes sense to get a new one so you don't have to deal with potential instability and other issues. Plus, running two video cards with it will place a heavy load on it.

 

[JimKiler]

That PSU is soon to be 8 years old. Since you want to run two video cards, I'd personally buy a new PSU. As they age, they lose some of their output power, and that unit came with a 5 year warranty. You easily got your money's worth out of it.

You have two sides when it comes to replacing a PSU before it dies. Some will say if it works, it's stupid to buy a new one, and use it until it shows issues or dies. The other side will say it's had a good run, capacitors age from heat and time, so it makes sense to get a new one so you don't have to deal with potential instability and other issues. Plus, running two video cards with it will place a heavy load on it.

I agree with upgradeing the SPU. I replaced my R9 260 GPU to a RX 580 and that was enough to cause my Enermax 10 year old PSU to send surges to my motherboard which shutdown and warned me so i upgraded my PSU to a titanium PSU.

 

[DietDrThunder]

So what would be a good power supply that will support two video cards?

 

[UsandThem]

So what would be a good power supply that will support two video cards?

Pretty much any quality 750w unit. Seasonic Focus Plus, EVGA G2 or G3 would be my recommendations. However, it looks like most just went off sale, so they look like they are all MSRP right now. For example, the Focus Plus was just $55 after rebate the other day.

 

[VirtualLarry]

I second or third the suggestion to replace with a newer, higher-powered unit, that has sufficient native power connectors for your needs. Adapters should only be used very sparingly, and only on PSUs with enough power.

Those are some very power-hungry cards you have in there. I had a pair of 7950 cards, on a 730W RaidMax semi-modular PSU. It ran, but not great. Really, the temps from those cards are worrysome if you have both in a rig, IMHO.

 

[MaikuTech]

So what would be a good power supply that will support two video cards?

Check out the system requirements tab on newegg.com, right off the bat they recommend 500watts.
https://www.newegg.com/Product/Product.aspx?Item=N82E16814202008
Since you have 2 in your situation I recommend 800watts to be on the safe side if you oc your cpu some.
https://www.amazon.com/gp/offer-lis..._name=3&mv_style_name=4&qid=1513180085&sr=1-1

May ask you somethings why exactly do you want to keep that 7970 ?
Its a great card I hear but I've seen people elsewhere have problems with it or mainly dying out due to heat problems.

This could be a better way of a step up from those cards if you wanted to upgrade next year.
https://www.amazon.com/gp/offer-lis...&sr=1-4-fkmr0&keywords=radeon+rx+560+sapphire

https://www.amazon.com/EVGA-BRONZE-...UTF8&qid=1513180845&sr=1-1&keywords=evga+600w

 

[DietDrThunder]

Check out the system requirements tab on newegg.com, right off the bat they recommend 500watts.
https://www.newegg.com/Product/Product.aspx?Item=N82E16814202008
Since you have 2 in your situation I recommend 800watts to be on the safe side if you oc your cpu some.
https://www.amazon.com/gp/offer-lis..._name=3&mv_style_name=4&qid=1513180085&sr=1-1

May ask you somethings why exactly do you want to keep that 7970 ?
Its a great card I hear but I've seen people elsewhere have problems with it or mainly dying out due to heat problems.

They play every game I have at max settings. There is no point in changing video cards until I change to 4K monitors.

 

[DigDog]

i'm checking some charts from back when and it looks like you want a good margin of 300w PER CARD, which then increases if 1. you have overclocked the card 2. your cards come pre-OC by model. So a 700W PSU *could* run them, but would eventually, and not far in the future, die.

it's not likely to blow up anything beside itself, but i wouldn't risk it. It's not a bad PSU either, but it's a 8 year old PSU from 2009, the capacitors are probably looking to retire, running it at nearly 100% draw will almost certainly result in it burning out.