Question about auxiliary PCIe power cable for installing graphics card

[opqpop]

Hi, sorry I'm a complete noob to graphics cards, but I am trying to buy a desktop and a graphics card. I've decided on buying either the Radeon HD 5670 or Radeon HD 6670 from reading the Best Graphics Cards Jan 2012 column on Tom's hardware (http://www.tomshardware.com/reviews/gaming-graphics-card-review,3107-2.html), but I was wondering what one of the statements meant:

The Radeon HD 6670 isn't really much of an upgrade over the Radeon HD 5670. However, we're going to give it an honorable mention for being the fastest card (at least compared to reference versions from AMD and Nvidia) that doesn't require an auxiliary PCIe power cable. That is to say its power requirements are entirely satisfied by a second-generation PCI Express x16 slot.

Does this imply if I buy a Radeon HD 5670, I have to also buy an auxilliary PCIe power cable, whatever that is? If so, how much are these cables usually? The ATI website says the requirement for 5670 is PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard.


Also, does the 6670 save me more power costs in the long run since it can be satisfied by a second-generation PCIe x16 slot? It says max TDP for 5670 is 61W and max TDP for 6670 is 66W.

Thanks so much

 

[Wolfshadw]

If you purchase an HD5670 (or any card for that matter) that requires auxiliary power, the card *should* come with a cable/adapter for your power supply and that is only needed if your power supply doesn't already have the proper power cable (PCIE 6-pin/PCIE 8-pin).

-Wolf sends

 

[Onus]

Neither card needs an auxiliary PCI Express power connector. It is a six pin (or 6+2 pin) connector found on most PSUs at or over around 400W.
The HD6670 is more powerful than the HD5670, but some would say not enough to justify its higher price. Personally, I think it IS justified, and here's why:
With a high-end card (e.g. a HD6970) that is already giving you 80+ FPS in a game, another few FPS makes no meaningful difference. On what many consider a low-end card like a HD6670, you're having to lower settings to get playable frame rates, so an extra few FPS may mean the difference on whether or not a certain setting can be used enjoyably, or even if the game is playable at all.

 

[Onus]

In general, I recommend against the use of adapters. If a PSU doesn't have a PCIE power cable, chances are that it doesn't have enough amperage on its +12V rail(s) to power a stronger graphics card. Using one or more adapters will just kill it, and such cheap PSUs tend not to die alone, but might take your motherboard, hard drive, or that nice new GPU with it into the fiery abyss. There are a few exceptions, but they are often a case of using adapters to get a second PCIE power connector when the PSU already has one. A good example would be Tom's use of a 430W Antec Earthwatts PSU with an adapter to power a HD6870: http://www.tomshardware.com/reviews/phenom-ii-overclock-graphics-card,3032.html

 

[Rockdpm]

It could be possible, that the card just runs solely off of PCI express power. Most of the time if the card needs PCI express 6 pin or 6+2 pint, the card will come with the connector. But Just make sure you PSU can handle any of those card which i'm sure u could run either of those cards off of the lowest 400 or 430 or 450 watt diablotek or whatever u run. but i do recommend a decent quality PSU for even the lowest grade cards. I have to systems, one is using a 550watt psu running a GTS 450 and a AMD Phenom X4 830. I am also running a GTX 560 ti SLI off of TX 750 with the new FX 6100 and a high end board. I have seen lots of people running stable at the lowest amount needed, however i don't recommend always doing it that way.

 

[alrobichaud]

http://www.tomshardware.com/review [...] 61-12.html

Basically, the standard rated power for a 6 pin pci-e connector is 75W. An 8 pin is 150W. The pci-e slot provides 75W. Doesn't look like either of those cards will require external pci-e power cables since they are below the standard 75W that the pci-e slot can provide. Most video cards will come with a pci-e power adapter in the box that will connect to one of your existing molex connectors if it is needed. I agree with jtt283 in regards to the adapters unless you know that the 12V rail on your power supply has a high enough amperage rating. This number is on the sticker on the side of your power supply. You will also find the amperage required for the card on the spec sheet.