Miner Starts, PC Reboots

[mattymaxx]

Hey Folks...

Just building a rig up for a friend...

A-DATA 1200w PSU
Gigabyte 780T-D3L (AM3+)
Sempron 140 2.7Ghz
2GB DDR3
80GB HDD

5x 5870 cards
1x16 risers (non powered)

3 gpus, the pc boots and runs perfect. Then mines perfect...

4 gpus, the pc boots and runs perfect. Then when miner starts, reboots

If I set intensity to 5 on the 4th card, it will mine (other 3 cards at I18) but as soon as I bring up the intensity... reboots.
I feel it may be a kind of power issue?

The PSU has 6x pcie connectors.

Using molex to pci-e converters for the 4th card, converters are on 2 different strands....

Is my issue a power one? are the molex lines not up to the job? Used molex to pci-e converters in the past without any issues...

The plan was to run 5x 5870s....

Any help would be brilliant atm as im a bit puzzle atm!

[mattymaxx]

ok, just tried using the converted strands on the 3rd card. leaving 2 dedicated pcie strands redundant...

Mines fine...?

surely 1200w is enough for 5 cards, if not at least 4 cards surely?

[Walking Glitch]

You need powered risers, four GPUs each drawing 75 watts from the mobo is too much, and even three will eventually burn it out. Also, 1200 seems a little on the low side for 5 5870s, I would go with a 1400 Watt PSU, but you might be able to squeeze them in if you udnervolt.

[mattymaxx]

I thought about powered risers... but the people in this video aren't using them:

http://www.youtube.com/watch?v=wZMiXeYQuAs

I also have 2 other rigs. 1 running 4x 5870 on a different mobo... Without powered risers with no problem...

Im happy to give powered risers a try, just seems unlikely?

[Walking Glitch]

I thought about powered risers... but the people in this video aren't using them:

http://www.youtube.com/watch?v=wZMiXeYQuAs

I also have 2 other rigs. 1 running 4x 5870 on a different mobo... Without powered risers with no problem...

Im happy to give powered risers a try, just seems unlikely?

Not unlikely at all. There's tro reaons for that; 1: Some motherboards can handle more GPU better than others, but four will almost always burn them out, or 2:Depending on how the VRMs work on a specific model of video card, they may prefer to draw power from the PCI-E power connectors, but most designs prioritize power draw from the mobo. 2 5770s and 1 6770 OCed like crazy was the most my friend's mobo could handle, as a fourth card on an unpowered riser was too much if he started mining with it, but that's 300 watts on something only designed to supply 150. My motherboard has issues supplying power to two highly OCed 5850s and an OCed Phenom II X6, I actually got a stable overclock on my CPU by undervolting from 1.4V to 1.375 at 4GHz. 1.4V was just unstable because the motherboard couldn't handle it. First an last time I buy an Asrock Extreme3 mobo.

[mattymaxx]

I See...

So am I best off using powered risers for ALL of the cards then, or just the last 2?

Any other opinions...? Or is this gonna fix my issue?

[gbx]

power supply isn't supplying enough power and causes the PC to restart.  I'd venture to say the amp draw causes a sag and forces the power supply to not supply enough electricity to keep the pc running.

try lowering intensity and underclock (or just don't overclock them).

[topminingcontracts]

I feel is one of two small power supply or temperature issue.

my 2 cents

TMC

[mattymaxx]

Really?

I thought 1200w would be enough for at least 4x 5870s!

What kind of wattage would be needed then!?

[HellDiverUK]

2GB is a bit slim, especially if you're going to mine scrypt coins (which is all 5870s are good for now).

[gbx]

Really?

I thought 1200w would be enough for at least 4x 5870s!

What kind of wattage would be needed then!?

Just basing it on my own experience.  I had an 850w psu I thought would do the trick in a 3 card setup.  Nope.  I think the rating on that particular PSU was a little generous.

Anytime a PC has rebooted when mining starts, it's always been (lack of) power related for me.

Also, you aren't using the Y splitter for the 4 pin molex connector are you?  The 1 molex to two 6 pin adapters?

[mattymaxx]

2GB RAM wouldn't cause a reboot tho would it?

I can perfect the config eventually, need it running first tho!

The A-DATA psu I have got excellent reviews though, bit puzzle by it!

Ill try the setup with a 2nd psu to see if it is the psu!

[philips]

Just a thought, if your PSU is a multi rail one make sure to have the load balanced between those rails.
If one rail is overloaded the PSU protection could kick in causing a reboot.

Also USE powered risers. Yes, you might get away with not using them (depending on the motherboard) but you might as well get your rig on fire (true story here on the forum many times).

[mattymaxx]

http://www.adata-group.com/index.php?action=product_specification&cid=4&piid=75&lan=en

Specs of psu I have...

Says 2x 12v rails... Not sure which strands its divide up into tho?

[tom_o]

I See...

So am I best off using powered risers for ALL of the cards then, or just the last 2?

Any other opinions...? Or is this gonna fix my issue?

Yeah you should only have 2 cards powered from the motherboard, even then that's >10 amps being supplied through 2 pins on the ATX connector then being routed across the board's traces to the PCI-E slots. Alternatively you could directly inject power to the slots by adding a 12V wire across the bottom of the board soldered to the correct PCI-E pins.

[Zemou]

Looks like the Jamaican motherboard smoked a bit too much...