Topic: 4x Radeon HD 6990 - page 2. (Read 10016 times)

I understand what he did.  What I don't understand is why most people are NOT seeing such issues.  I have shuffled my cards around quite a bit with my ASUS Rampage III Gene and there is no sign of warping, discoloration or any damage what-so-ever.  The slots are never even warm to the touch [or the board if I happen to touch it].  You have to reach down to unclip the card to get it out, so I have little doubt that the board integrity is sound.

Maybe older boards that are closer to spec or lower quality suffer from this issue as opposed to better and newer boards?  Like I said, my board gives out a shrill squeal if you attempt to boot with too much power draw [found that out after shuffling cards and forgetting to connect the power to the video card ... when I was experimenting with two cards in my case (answer is too hot and need a larger PSU)].  Even if there is enough power to boot, the board will disable the heavy card [in my case the 6970] when it detects that it can't adequately keep it supplied with sustainable power.  

Anyway, it is good to know.  I am sure the NVidia 580GTX and 590GTX have similar power consumption [if they know it is there, they will use it].

Haha... no.  PCI bus limit is about 75W.  These have dedicated 8 pin PCI-E connectors.

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The problem I see with 4 of these in a system is heat and the fact that 2000W = more than a 15A breaker will handle.  I'd say your best bet would be 2 rigs.

Plus if one goes down, everything isn't down.  Much better for reliability.

Yes, they do indeed draw power from the PCIe connector, even though they have additional power connectors.

He is referring to the ATX power spec.  12v power for PCIe slots is provided by only two pins in the ATX power connector, rated for 6 amps each.  He was pulling 7.4 amps over each pin, which was melting the shroud and likely caused permanent damage to his motherboard.  It probably would have started a fire eventually if he hadn't been actively watching it.

His solution was to bypass the ATX plug (and motherboard) entirely by spicing his PCIe extenders to accept power directly from the power supply.

Thanks for the link. 

I do wonder though, is the spec he is referring too 1.0, 2.0, 2.1, etc?  Are they even different in this respect [I haven't looked].  All I know is that my motherboard has absolutely no problem with the 5970 [slightly over-clocked core, but no tinkering with voltage].  My board will make a loud squealing sound at start up if there is too much power draw [and a red LED lit up somewhere that I couldn't see, but the power was always cut to my 6970 when I tried to put a 5850 in with it [I was pushing it with a solid 750W power supply anyway].  I suppose cheaper motherboards would just lock up outright.  Anyway, I suspect most recent boards work with AMD and NVidia and know what their upcoming products are going to be like and they design accordingly.  That article indicates a considerably higher draw on current though and that really doesn't make a lot of sense to me since I am not sure a board could be designed that much over spec without adding additional PSU connectors to the board [or the PSU itself also tends to be overspec for the very same reasons].  One thing you know is that AMD chipsets on most motherboards are going to support the new video cards that AMD is making, and thus, so will Intel, VIA, etc.

I am not an electrical engineer [or an electrician] and have only some mathematical knowledge of electronics via a couple of EE courses in college, so I may really have no clue what I am inferring here 

http://blog.zorinaq.com/?e=44

Why?  They don't draw power from the PCIe bus, they have external power inputs [8 and 6 or 8 and 8 .. not sure which; my 6970 has 8 and 6].  You are the first that I have heard indicate that the card somehow draws more power from the bus than spec allows for.

BTW, a decent motherboard will simply refuse to bring a card online if it is energy starved.  I have found this out for myself ASUS Rampage III GENE (small little thing, but a very nice board for what it is).

Also they will draw more power than specified via the PCIe slots, so you might kill your hardware this way.

Someone has probably tried it somewhere. You would definitely need about 2000 watts between at least 2 power supplies since overclocked they pull close to 400 watts a piece

will work only on linux as windows has 4 gpu cores limit
basically no different than http://blog.zorinaq.com/?e=42

Has anyone tried?