Amperage on 12v rail to run ati 5850

I've just bought an XFX ATI 5850 Black Edition and I'm not sure about the power supply requirements.How much amperage do i need in 12v rail? I'm thinking about a thermaltake 500W. Will it do the job. Also will Core i3 bottleneck the card?? Please help me with anything you can?
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  1. Thermaltake are not so great. You can run it on a CORSAIR CMPSU-450VX or the SeaSonic S12II 520 Bronze, around that price.
  2. Whatever you do get a PSU with a SINGLE rail.

    Something like this :






    don't skimp on the PSU =)

    I have been running Thermaltake PSU's for about 3 years and to this date everything has been great, problem is they are overpriced. But they also carry a 5 year warranty ;)
  3. You are running this PSU?

    That one will be just fine. One rail at 25A and another at 18A. If you plan on OCing, put your HD5850 into the one with 25A, otherwise, 18A is fine. Just make sure that you know whatever one your CPU plugs into (which rail goes to your CPU), and put your graphics into the opposite one.
  4. shadow, you can't select which rail quite so simply... Which peripheral leads are connected to which rail is nearly impossible for the end-user to figure out without tearing PSU apart and using a test light to check every circuit. But as soon as you open it up, your warranty is void, so it's kinda crazy to even think about it.

    I personally suspect that the 12V1 25A rail powers the mainboard, the 4+4-pin CPU lead, and peripheral leads. Meanwhile, the 12V2 18A rail has the PCIe power cables. But, that's just a guess. Only Thermaltake knows for certain, and I tend to doubt they even have that information available.

    Some of the really good multi-rail PSUs are actually labeled to indicate which leads are tied-into which rail. Unfortunately, this is not one of them.
  5. That is why you should always opt for a powerful 1 rail PSU. PSU's that have multiple rails are really not up to par when paired with a high-end GPU's, especially when you are overclocking the whole rig.

    I have have seen PSU's with multiple rails over 750w that cannot even push dual GTX 260's nor a single 470.
  6. Well, yeah... But those tend to be really the sh*tty ones with like 50A on the 3 or 5 volt rails, too. LOL
  7. Which rail is what is probably found in a .pdf file associated with the PSU.
  8. Not really, most PSU's that have mutiple rails are really not made for power gamers/users.

    IMO if you are going to use one or more Tier 1 GPU/GPU's you need a quality 1 rail PSU.

    For example I have an old TR-850w PSU that has 68A (4 rails), the PSU cannot handle a single 470/480. Also had issues pushing dual 5850's, so IMO if you game and you want a future-proof PSU stay away from multiple rails.
  9. Possibly shadow, but you'll have to go through their tech support email system to get any results. That can and likely will easily take days for an appropriate response, despite specifically asking for very precise and finite information up front. Meanwhile, a different PSU you don't have such concerns about would already be on a UPS truck and on it's way.

    I shouldn't have said the info isn't available. I should have said it's never readily or freely available on their websites or within the product manuals. I'm certain if you manage to contact the actual "Guru" of their tech support department he/she could provide the information. But, how long it might take to actually get that information is an unknown factor I'd rather not have to ever deal with.
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