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I'm not sure if we're allowed to ask questions as specific as this, but I hope so. If not, please tell me in the comments and I'll delete it.

I'm planning to upgrade my Radeon 6670 to a Radeon 6870, and I am currently running on a 500W PSU. My current configuration is:

  • 3,6GHz x 4 FX-4100
  • 4GB x 2 DDR3
  • 500GB HDD
  • One fan in the front (About the size of an index finger in diameter) and a few small blue LEDs
  • Radeon 6670 as previously mentioned
  • A WiFi card plugged into one of the PCI(-E) slots.
  • An extra USB bay with more audio jacks
  • A multi card reader (SD and the like)
  • Some DVD drive, not sure what specific type it is

My question is, of course, can my current configuration handle this upgrade (An estimate is fine, since I don't think my description of the parts is specific enough to warrant a specific answer, but if you could tell me how much margin I'd have (Ie "You'd probably have 50W - 100W to spare") I'd really appreciate it!

I ran it through a calculator and it said I'd be using something like 380W, but a human reply would be much appreciated

Also, I'm not sure if we're allowed to ask multiple questions on one, but I don't think this warrants another question and I think it'd be a quick yes/no answers: One being, would I notice a big difference between my current card and the 6870? I'd be using it for Source games and Minecraft, and also some 3D rendering.

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up vote 2 down vote accepted

For this sort of thing I like to use this page to compare power usage: Comparison of AMD graphics processing units

The Radeon 6670 is apparently a 66W TDP card while the 6870 is 151W. This is rather a substantial increase, though I would expect that given the other components in your system a 500W PSU should be able to handle it.

I have a 350W PSU running a Core i7-860 (same TDP as your FX-4100 by happy coincidence) and most of my other components are similar. My graphics card is only rated at 120W so is not much different, but the main thing is to make sure that the power supply can give more current on the 12V rails as that's where the graphics card will draw the most from.

I expect you will be fine with a 500W power supply, the higher PSUs tend to be needed for dual graphics card systems and at the worst case you might need to replace your power supply a bit sooner and that would probably cost about 1/3rd to 1/2 that of your new graphics card.

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I'll need to upgrade my PSU whenever SSDs become a bit more affordable so I'm not too worried about the lifespan providing it doesn't kill the other components of my computer or expire within a few months/year or two. Thanks for the advice though, feel a bit more confident about it knowing this. – Ashley Davies Aug 24 '12 at 17:23
Thanks for that Wikipedia link too, not too versed in the specific specs of graphics cards but judging by nearly all of them being about double I'd guess there's a massive performance improvement. – Ashley Davies Aug 24 '12 at 17:28
-1. TDP is not the same as power consumption. – Indrek Aug 24 '12 at 17:30
+1 for the 12v rail, regardless of total wattage if the amps on the 12v rail are too low it won't work. This is something power supply calculators do not take into account. – Not Kyle stop stalking me Aug 24 '12 at 17:39
@Indrek while TDP may not be an indication of power consumption is it an indication of power wasted via heat, which is probably the closest you can get to measuring power requirements in a real system. It may not be as good as an exact figure but it is a pretty good indication. – Mokubai Aug 24 '12 at 17:53

According to the AMD website, this card has the following requirement;

500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for AMD CrossFireX™ technology in dual mode)

First of all, your PSU is the minimum requirement. Also, if you are planning to run CrossFireX, it will not be sufficient. If you are at all concerned about it, upgrading will definitely not hurt you.

Another thing you may want to verfiy is the requirement;

PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard

Make sure you have that type of slot available.

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I'm going to swap the slot out with my old 6670 so it should be fine, and luckily it has an empty space below it (Since this card seems quite wide) which I have no use for. Thanks for pointing it out though – Ashley Davies Aug 24 '12 at 17:26
Do you have two 6 pin connectors? I don't think the 6670 uses them... – Not Kyle stop stalking me Aug 24 '12 at 17:38

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