Non Powered Risers vs Powered Risers & > 4 Card setups

YipYip

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Quote from: rograz on May 04, 2013, 10:25:44 AM

Quote from: YipYip on May 04, 2013, 06:20:55 AM

All my cards are 200watts + so 4 card rigs are @ 1000watts+

If it is not power then I am doing somthing majorly wrong or the msi 990fx dg 80 and 990fxa ud 7 boards are crap which i am not even going to go there type of deal

Powered risers are hopefully my answer to my unicorn of 5 7950 vortex saphires on a msi 990fx gd 80 v2 board

Like I said under those circumstances you should def use powered risers, very few motherboards can handle those loads, and the atx 24 pin connector will def be at risk (like you already experienced)

100-150W per card however seems to be alright even with 6 cards on a decent motherboard, else I would probably have killed quite a few boards during the last 2 years. Only been running scrypt since feb though so maybe they will all melt this coming summer ;P

So a warning to All..................!!!!!!!!!!!!!!!!!!!!!!!

My mate had a board with some 6990's and 6950s (6990's are the most watt hungry cards that I know)

He fried 2 ATX PSU connectors in 3 days before we looked closely to see the problem (our bad Sad

) ...the 990fax UD7 board is still fine ...lol (they make em tough)

1 psu is ok as it was AX1200 and have been able to order a new mobo ATX connector for the psu

The second has it attached...the casing is melted and the wire for about 5 mm is scorched (not black) is this still usable or can u repair it ?

And finally would they cover it under warranty Cheesy

(its only 3 weeks old ) ?

rograz

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Quote from: YipYip on May 04, 2013, 06:20:55 AM

All my cards are 200watts + so 4 card rigs are @ 1000watts+

If it is not power then I am doing somthing majorly wrong or the msi 990fx dg 80 and 990fxa ud 7 boards are crap which i am not even going to go there type of deal

Powered risers are hopefully my answer to my unicorn of 5 7950 vortex saphires on a msi 990fx gd 80 v2 board

Like I said under those circumstances you should def use powered risers, very few motherboards can handle those loads, and the atx 24 pin connector will def be at risk (like you already experienced)

100-150W per card however seems to be alright even with 6 cards on a decent motherboard, else I would probably have killed quite a few boards during the last 2 years. Only been running scrypt since feb though so maybe they will all melt this coming summer ;P

gyverlb

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Quote from: rograz on May 04, 2013, 03:28:55 AM

Then that must be some really shady motherboards ;P

The power specs for 1x connectors are simply lower than for 16x connectors.

So if you have a motherboard that largely overshoot the power specs for its 1x PCIe connectors you are fine, if not it will melt.

YipYip

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Quote from: rograz on May 03, 2013, 06:31:49 PM

Personally I've mitigated the 24 pin connector risk by just soldering a cable with a molex connector directly to the back of the the motherboard 24 pin solder point for the 12v, the 24 pin connector used to get quite hot in some of my 6 card systems but after this mod they don't heat up at all) The problem is usually resistance in the 24 pin connector and not the cable itself (unless its a psu with low quality cables) I've also never heard of the power lanes on the motherboard giving up so they should be fine.

The only situations you really need powered risers are when using dual gpu cards/heavily OCd single cards (they can burn the riser cable itself if there is to much resistance, depends on quality of riser cable as well) or got a system that is pulling 1kw+ in total.

I was also toying with the idea of putting copper paste in the 12V slot of the 24 pin connector, but I figured the risk of shorting it with other cables wasn't worth it (copper paste can get quite messy :/) so I just soldered an additional cable to the back instead.

@ 2+ m (scrypt) all my rigs are 1k+

Just found that when the boards\cards are fresh (msi 990fxa gd 80 v2 ) they are cool with 4 cards 2-3 on risers ..then after about 2-3 weeks they start to drop cards

I really think its power related ...also burning through the ATX connector to the mobo on the power pins also sort of points me in this direction

All my cards are 200watts + so 4 card rigs are @ 1000watts+

If it is not power then I am doing somthing majorly wrong or the msi 990fx dg 80 and 990fxa ud 7 boards are crap which i am not even going to go there type of deal

Powered risers are hopefully my answer to my unicorn of 5 7950 vortex saphires on a msi 990fx gd 80 v2 board

rograz

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Then that must be some really shady motherboards ;P Though saying that most of my boards are 3-4 PCIe 16 slot boards so might be why I've not had any problems with it as you say. I've got 1 Asrock 1155 board with just 1x16 slot PCIe and 5 1x slots that's been doing fine on scrypt for months, could be that it houses my old 58xx cards rather than 7950s though.

Might also be that I keep my 6 card rigs below 7-800W as a rule, the 58xx rigs are even below 500W with 6 cards. I've always more been after efficiency than max MH/value from OC, I could house more hashrate that way.

A word of warning for anyone going with non powered risers as well, make sure you got GOOD ones. If they get hot to the touch due to the current flowing trough them either toss them out or turn them into a powered one (make sure the lenght of the cable you use from the riser itself is as short as possible for less resistance). I had some really shitty no brand ones that couldn't handle 5970s back in 2011 then I switched to lotus ones and they have been working flawlessly.

gyverlb

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Quote from: rograz on May 03, 2013, 06:31:49 PM

Personally ive mitigated the 24 pin connector risk by just soldering a cable with a molex connector directly to the back of the the motherboard 24 pin solder point for the 12v, the 24 pin connector used to get quite hot in some of my 6 card systems but after this mod they don't heat up at all) The problem is usually resistance in the 24 pin connector and not the cable itself (unless its a psu with low quality cables) I've also never heard of the power lanes on the motherboard giving up so they should be fine.

You should tell that to the 12V lines of the last motherboard I fried... it's easier to engage in conversation now that they burned through the PCB :-/

It's not a defect either: I have 2 other motherboards of the same model and they both have the 12V lines heating more with each non-powered 1x->16x riser I add.

Quote from: rograz on May 03, 2013, 06:31:49 PM

The only situations you really need powered risers are when using dual gpu cards/heavily OCd single cards (they can burn the riser cable itself if there is to much resistance, depends on quality of riser cable as well) or got a system that is pulling 1kw+ in total.

It depends on your motherboard model. Cheap ones, especially with more 1x slots than 16x slots aren't designed for the kind of abuse sha256d and especially scrypt mining put them through. Note that at least reference 5870s and probably other 5xxxx and maybe most cards power the memory through the PCIe connector : when you underclock the RAM you hide the problem, switch to scrypt and high RAM freqs, fry the motherboard...

It's less costly to use powered risers than expensive motherboards or fry cheap ones...

rograz

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Personally I've mitigated the 24 pin connector risk by just soldering a cable with a molex connector directly to the back of the the motherboard 24 pin solder point for the 12v, the 24 pin connector used to get quite hot in some of my 6 card systems but after this mod they don't heat up at all) The problem is usually resistance in the 24 pin connector and not the cable itself (unless its a psu with low quality cables) I've also never heard of the power lanes on the motherboard giving up so they should be fine.

The only situations you really need powered risers are when using dual gpu cards/heavily OCd single cards (they can burn the riser cable itself if there is to much resistance, depends on quality of riser cable as well) or got a system that is pulling 1kw+ in total.

I was also toying with the idea of putting copper paste in the 12V slot of the 24 pin connector, but I figured the risk of shorting it with other cables wasn't worth it (copper paste can get quite messy :/) so I just soldered an additional cable to the back instead.

YipYip

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Ok here are some answers

on one of my rigs (4 6970 setup) i just burned through my ATX main board 24 pin connector to my AX1200 PSU ..I was lucky it was only the cable Shocked

Solution : Get powered risers or run Max 3 Cards per mobo

I think all the issues I have been having are power related so waiting on 26 powered risers arrive in 2 days Cheesy

A1->B17 short fix's the 1 x slots so now all my MSI 990fxa gda 80 boards can theoretically run 6 cards

I am going to shoot for 5 x 7950 vortex Saphires once the powered risers come

Check on the boards for instructions on how to make your own instead of the $18 on Cablesaurus

Also 13.1 drivers seem to be a better target

Also 96 pci-latency

Disable everything in bios excepct for NIC ...i.e USb 3, audio

There is light at the end of the tunnel Cheesy

YipYip

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To ask a couple of $64,000 dollar questions that have been driving me nuts

Are Powered risers the answer to these type of issues

BTW I am running all newish (< 2 months old) hardware

VTX 6970's
Saphire 7950 OC Boost Vortex

When trying to run 4 cards on risers (MSI 990fxa GD80) the 4th card will drop off after a while and long story short u have to drop it back to the mobo to get the rig stable ... u end up with best case 3 on non-powered risers and 1 on the board ... (as they get older 2 on board and 2 on risers etc ) I take it that there is no enough extra power from the mobo getting to all 4 cards risers add another level of overhead to this problem

And finally Long story short powered risers will fix this bullshit

This being true (please say its so ) i should be ok with a shorted A1->B17 and powered 16-> 1x riser on the 1 x slots on the gd 80 and also be able to get 6 gpu's (7950's) per board ??

Topic: Non Powered Risers vs Powered Risers & > 4 Card setups (Read 2711 times)