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GA-EP45-DS3 + some PSUs = don´t boot


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I have the problem that my motherboard GA-EP45-DS3 is in conflict with some power supplies and will not boot. The power supplies are working properly.


GA-EP45-DS3 Corsair vx550 + (3.3 V/30A, 5V/28A, 12V/41A,-12V / 0.8 A, 5Vsb/3A) does not boot

GA-EP45-DS3 + be quiet! Dark Power Pro 600W (3.3 V/28A, 5V/40A, 12V/40A,-12V / 0.8A,-5V / 0,5 A, 5Vsb / 2.5 A) does not boot


but the "bad" power supplies


GA-EP45-DS3 + CP 650W (3.3 V/28A, 5V/28A, 12V/18A,-12V / 0.8 A, 5Vsb / 2.5 A) works fine

GA-EP45-DS3 + Xilence 450W (3.3 V/25A, 5V/28A, 12V/18A,-12V / 0.5 A, 5Vsb / 2.5 A) works fine


How can it be that my MB with good power supplies and high amps will not boot, but with rather poor power supplies is doing just fine? I already checked the grounding on my case, so this can´t be it. I would keep my current Xilence PSU, but I need a new one soon, because a new graphics card is pending which needs 2x PCIE connectors. I don´t want to buy a good power supply (again), with which my MB doesn´t work. I have read something about required-5V, but the GA-EP45-DS3 is not too old that it needs -5V?


I would be grateful if someone could tell me what I have to look out for on my next purchase of a power supply or whether I should buy a new mainboard because it is a known Gigabyte problem (I have googled a lot but found nothing relevant)?


best regards

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I have the problem that my motherboard GA-EP45-DS3 is in conflict with some power supplies and will not boot. The power supplies are working properly...


I have read something about required-5V, but the GA-EP45-DS3 is not too old that it needs -5V?...


best regards


Well, a quick check of your mother board's manual shows the board's 20+4 pin connector expecting -5V on pin 20. See page 22. It probably does not use the -5V power, but if it is absent that seems to be seen as an error and no boot is attempted.


Since we don't know the model numbers of the PS's that work with this board, we can't check if they supply -5V on pin 20 of their ATX connector.


Apparently this board is a very early socket 775 design, from mid-2008.

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thank you so much for the replies:)


Sorry I didn´t post my specs before but I thought it would be irrelevant since the system works fine with some PSUs.



CPU: q9400 2,66 GHz @ 3,2 GHz OCed

RAM: ******** Reaper 2x2GB 1066 (********2RPR10662G)

Grafik: HIS Radeon HD 4850 1GB - soon to be Zotac GTX 560 Ti 2GB

And connected only a HDD and DVD burner


The PSU´s model Numbers are:

Corsair - CMPSU-550VX

be quiet! - BQT P6-PRO-600W

Xilence - Redwing Series XP450

Inter Tech - Combatpower CP 650W 88882016

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Well, I wasted my time checking the two old style power supplies that work with that board, one has almost more power available on the 3.3V and 5V rails than the 12V rail, identifying it as the old style CPU power supply. The other PS specs are in German.


I guess you did not understand my last post. Your mother board expects to get -5V power from the power supply. It shows that in your boards manual on page 22. The old Xilence and CP power supplies have -5V power.


If your board does not get -5V power, it will not boot. Your board will only work with old power supplies.


All new power supplies, and most power supply's even three years old, do not provide -5V power, that is now obsolete. Most mother boards have not used -5V power for three years, none of them do now.


Your Corsair power supply and the be Quiet do not provide -5V power, so your board will not boot if you use them with it. No new power supplies have -5V power, so they will not work with your board.


This is not a Gigabyte problem, but a compatibility issue. Your board needs an obsolete ATX power supply specification, that can only be provided with old power supplies. You cannot buy a new power supply that will work with it. There is nothing wrong with your Corsair power supply.


You will never be able to power a Zotac GTX560 with your old power supplies, they do not have enough +12V power. I think you know that, which is why you bought new power supplies. But they won't work with your board.


You should consider getting a new mother board, and maybe a new CPU. Your board was one of the first socket 775 boards, and is one of the first steps beyond a Pentium D, which cannot be used on your board. Unless you can find an old power supply that has high +12V power, and -5V power for your board, a GTX560 will run out of power once you put it to work.

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Wow I thank you sooooo much:D


I can´t believe there was actually an identifyable reason for that problem since I have read so much over the days with many people having similar problems, but none could find out what it actually was.


Unfortunately I can´t afford a new MB+CPU(+RAM) right now, so I will try to find a PS that might fullfill the criteria.


Again thank you soo much - you have solved the despairing riddle to the problem many other people have too and maybe this thread will bring clarity to them.


Best regards:)

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Btw how did you find out about the mentioned PSUs having -5V or not? As I posted for example the be quite PSU´s specs are:


be quiet! Dark Power Pro 600W (3.3 V/28A, 5V/40A, 12V/40A,-12V / 0.8A, -5V / 0,5 A, 5Vsb / 2.5 A)


Is this what you are referring to? And when I go the the manufacturers` sites Inter Tech and Xilence, I can´t find the -5V for my PSUs. Or is it just that my Inter Tech and Xilence PSUs have higher power on the 3.3V and 5V rail, concluding it to be an old style PSU thus having -5V?

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Thanks, and sorry I did not post what I found about those power supplies. Here is a review of the bq! Dark Power Pro 600, scroll down to the picture with the label describing the power distribution specs:




It supplies 0.5A on the -5V rail.


I can't find anything about the Xilence PS, although it still seems to be being sold all other Europe and Asia.


The Corsair VX550 does not have a -5V rail, although it is a pretty old PS (in PC years...)


My conclusion was based on:


1. Your mother boards manual shows it needs -5V on pin 20.


2. Your PC boots with the bq! PS, which has a -5V rail.


3. Your PC does not boot with the Corsair PS, which does not have a -5V rail.


Yes, not a big set of data or power supplies, but it seems obvious to me. Sorry the other PSs don't work for you.


You should be able to find a socket 775 mother board that does not need -5V power, they are very common. So you would not need to replace most of your PC. Just be sure it uses DDR2 memory, as some boards like this use DDR3.

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