Should I SLI and can my PSU handle it

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Net1x

Net1x

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Jan 7, 2014
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Hi there,

I would like to add another GTX 670 (I could get a used one for 140$(worth it ?)) but I'm not sure if my PSU can handle it and if I would get a net advantage with two GTX 670. I'm running all my game on a 27inch display (2560 x 1440) and right now i'm getting 30 fps on AC: Unity (High Settings) and around 35-40 fps on Dragon Age Inquisition (High Settings). Would I be able to OC the cards and the CPU ?

Here's my rig :

i5 3470 ivy bridge
Asus P8Z77-V LK
16 gig ddr3 ram
Asus Gtx 670 2gb
Corsair TX650w

1x Intel 730 480gb
2x 3TB WD Green
1x 2.5TB WD Green
1x 1TB WD Black

6x Fan 140mm
1x Corsair H80i CPU Cooler

Thank you for your time




 
Solution
TheMentalist
For running 2 GTX 670's in SLI nVidia recommends a power supply that has a maximum combined +12 Volt continuous current rating of 42 Amps or greater, also 700W minimum. The TX650 V2 has a single +12 Volt rating of 53Amps. The wattage may be on the lower side(650W) but using the PCI-E 6pin to 2x6pin or 2x molex to 6 pin should work by definition.

I checked it and your power supply is a single rail unit. The molex adapter and the PCIe splitter should work. I'd go for the molex adapter instead to be safe and not overclock the system.
http://www.amazon.com/HDE-PCI-Express-Pin-Molex/dp/B002CZANA8
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TheMentalist

TheMentalist

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650W is enough for 2-way GTX 670. You'll not be able to overclock them. The power supply will be peaked allot though.
However your power supply comes with 2 6+2pin PCIe connectors. It won't be enough for a second 670.

Rule of thumb, 500W minimum for single 670 + 170W(non-overclocked GPU's) for second.
You can go with a 750W power supply for it to run safe and have enough cables.
Here's a review on 670 SLI: http://www.guru3d.com/articles-pages/geforce-gtx-670-2-and-3way-sli-review,4.html
You'll roughly pay $220 for a new PSU and the extra 670.

The thing is, if you're gonna do 1440p chances are that the 2GB won't cut it. Especially with future games.
The money you'll pay for the extra 670 and PSU can be used to get a stronger single card. You can save up some money and get something like a 290X/970. You won't need another PSU for that.
The SLI setup may give you the same amount of frames/second but you should take the frame time variance also in account.
50fps on a single strong card will feel smoother compared to 50fps 670 SLI.
 
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Net1x

Net1x

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Jan 7, 2014
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Thanks for the answer TheMentalist,

Would I be able to power the second GTX 670 with molex to PCIe adapter ? Or it's not recommended ?

If I dont OC those cards, is it still worth it to pay 140$ to get another 670 to go through another year of gaming ?
 
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TheMentalist

TheMentalist

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I don't recommend using molex adapters. Especially with high wattage components.
I'm not sure how the 12V rail(s) on the power supply will handle it. I'll look into it though.
Even if you would run another 670 I'd recommend saving some money for a bigger upgrade.
My biggest concern is the 2GB VRAM on 1440p. Don't get me wrong, GTX670 SLI is beast but if you're gonna upgrade now, there are some better options available. If you can safe some extra money and get a stronger card you'll be ok for a good amount of time.
 
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Net1x

Net1x

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I guess I should save some money and get a better card, you're right.

Would I get an advantage if I OC my present GTX 670 and my CPU ?
 
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TheMentalist

TheMentalist

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Yes you get some extra frames if you overclock them, especially the graphics card rather then the CPU.
Not too much fps but it's definitely an improvement over stock.
Look for some tutorials on overclocking your GPU, keep your components cool and you'll be ok.
 
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Net1x

Net1x

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Jan 7, 2014
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Just saw that my psu is the tx650 v2 doesn't know if it changes something... I would still have to power the second gpu with molex to pci-e connector (some came with the GPU itself).

Do you recommend those ? http://www.amazon.ca/StarTech-com-PCIEXSPLIT6-6-Inch-Express-Splitter/dp/B004NNTVT6
 
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TheMentalist

TheMentalist

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May 13, 2013
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For running 2 GTX 670's in SLI nVidia recommends a power supply that has a maximum combined +12 Volt continuous current rating of 42 Amps or greater, also 700W minimum. The TX650 V2 has a single +12 Volt rating of 53Amps. The wattage may be on the lower side(650W) but using the PCI-E 6pin to 2x6pin or 2x molex to 6 pin should work by definition.

I checked it and your power supply is a single rail unit. The molex adapter and the PCIe splitter should work. I'd go for the molex adapter instead to be safe and not overclock the system.
http://www.amazon.com/HDE-PCI-Express-Pin-Molex/dp/B002CZANA8
 
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Solution
Net1x

Net1x

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Jan 7, 2014
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One more question, I've looked the cables inside my PC. I've got two stripes of molex cable coming out of the PSU. I guess I should install 1 Molex Adapter (2 molex to 1 PCI-E) on each stripes ? Does it matter if I have my case fan controller plugged to a molex on one of the stripes or It have to be empty ?
 
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