Help Needed

Hello, I recently asked the forum for advice on a new graphics card, link:

That has all the information.

I went and bought the Sapphire 3850.

I uninstalled my previous graphics card drivers (the Nvidia Geforce FX 5500), was prompted to restart, I clicked OK. Nothing happened. I waited 10 minutes just incase, still nothing. I went ahead and cut the power off. Powered back on, screen was bigger as expected, then tried to shut down again. Still nothing.

I took out my old graphics card, placed the new one in and booted up. Now it wont stay on for more than 2-3 minutes. It just shuts down as if someone pulled the power cable out.

The new card has to be connected directly to the power supply, the box says 450w minimum, mine is 600w so I doubt that is the problem.

The card did come with cables to connect it to the PSU, but there are 2 x 4 connectors. Each one has 4 holes but 3 metal pins. Do I only need to connect one of these to the PSU, or both?

Any help would be greatly appreciated as I am puzzled. :(

I even put my old graphics card back in, and it still wont stay powered on for more than 2-3 minutes.
14 answers Last reply
More about help needed
  1. Correction: I have a 500w PSU.
  2. Will the machine stay powered on if you go into the BIOS setup?
  3. I did try going into the BIOS to see if there was anything about integrated graphics (before posting here, as I did read that needs to be disabled), but it shutdown then too (Does the P4 630 have integrated graphics?). I powered it back on 15 minutes ago and it hasn't turned itself off yet. Fingers crossed.

    The question I'd like an answer to, if it does stay on, is do I need to plug both connections into the PSU or just one, as I only have one available slot for it, which was for my DVD player, but I can do without that for now. If not, will I need to buy a cable that will allow me to plug both in?

    Here is a picture of the power cable that came with the card:

    I just checked my computer and low and behold it has turned itself off again (with the 3850 card in).
  4. You need two spare molex feeds for that lead, but if the machine will not stay powered up while in BIOS then you either have a power, heat or shorting out issue to deal with first. Check that you did not knock any plugs/connectors loose, and how old is that PSU? and have got a spare knocking about?
  5. The PSU is an ATX-500. It's about 2 years old. Everything was fine until I uninstalled the old graphics card and the computer would not restart. I've double checked all the connections. I clean the PC out every month, so I know what should be connected and what should not. I'll go check again, just incase hehe. Knowing my luck I WILL have missed something.


    12A Max
    6A Max

    +12V 22A Max
    +5V 38A Max
    +3.3V 30A Max
    -5V 0.5A Max
    -12V 1.0A Max

    +5V/SB 2.0A Max

    Thanks for trying to help! It's appreciated. :)

    Edit: Is there a cable available that you can plug into the one spare molex feed that will provide two molex feeds for the card, or will I need a new PSU?
  6. Might be your psu, 22A over the 12V and considering it is 2 years old it might not be able to give anywhere near the 22A it could before.

    You might try it with another branded psu to be sure to isolate it as the sole problem.
  7. The graphics card requires 30A over 12V. Just noticed this... but, even trying my old card, which has worked without any problems thus far, it still turns itself off. Will reinstalling the drivers for the GeForce FX 5500 maybe resolve this problem until I get a new PSU?

    Can someone suggest a branded PSU that I should consider? One with plenty of molex feeds preferably. :P lol
  8. I like the Corsair range myself, a HX550 if you want modular or VX550 if you prefer fixed cables both can provide more than enough amperage for your setup.
  9. Thanks. Do they work with any motherboard, etc?

    My PC specs can be found on the link I provided if needed.

    No idea what the difference is between modular or fixed cables. Sorry, hardware side of things is not my speciallity lol :(
  10. Yes, they 'universal' and so it should be a straightforward swap.
  11. Nice. Thanks for all the help. :)
  12. No problem, fingers crossed it is just the PSU choosing an inopportune time to call it a day.
  13. Sorry, back again.

    I hope so lol I did open up the PSU, turned the PC on with only the power connected and it stayed on for a whole hour, until I turned it off myself. That's with the old card in, though. Gonna install the drivers for the old card and see how it goes.

    Anyways, I was wondering if the HX620 or HX650 would be a better option, since I can't find the HX550 anywhere in the UK (through Google). Plenty of websites selling HX620 and HX650, though.

    Keep in mind the new graphics card needs 30A over 12V rail.

    Edit: Searched around for information. The Radeon 3850 box says I need 2x4 power connector.

    The HX620 and HX520 have:

    x 1 24 Pin + P8/P4
    x 2 PCI-e 6/8 Pin
    x 8 SATA
    x 10 Molex

    (4 SATA on the HX520).

    Will the card fit this PSU?
  14. Here is a HX550, and I can highly recommend the HX620 as I have two of them but unless you are going to be running a shed load of HDD's or a dual GPU set-up, do you really need that much?
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