PSA: Malta 7990s are NOT suitable for mining!

[dogie]

Hello all. After my experiences with 2x partner card (PC) non Malta 7990s, I wanted to raise my concerns about the new Malta (M) versions. I hope one of my first threads is useful to the community.

Mining:
Just for reference, at 1050 cores I get 1280 per card for ~400W from the wall.


Pricing:
So the PC cards come in at about $900, 7970s at $400. This means they are viable for limited space internal card builds and will possibly hold their value better as they'll stay in the usable performance bracket longer.

The new M cards come in at $1000. Although they have more games, its pushing it a bit. Not a problem, but something for each to evaluate.

Tldr: New M cards more expensive, but have more games.


Temperatures and cooling:
Partner cards are 3.3 slot and weigh nearly 3kg each. This means they do NOT work without at least a full slot gap. Most motherboards don't have a usable non-riserable slot in the first expansion slot, so you require an 8 slot case. Not a problem.

They take up 3 slots AND the typical gap between the bottom and next slot. Running without a free gap you can only mine on 3 cores. Regardless of the underclock, TDP limiting, undervolting or intensity, the 4th core always overheats.

With a gap the bottom card loads at +45-50 above ambient, and the top card +55-65 above ambient. [Note I don't have voltage control of the 2nd core on each card, hopefully this will arrive with newer drivers as I have control when there is only ONE card - this will improve temps slightly]. This is with a 1050 core, undervolted.

Now the new M cards have dual slot coolers, ouch. At stock clocks they were loading just below the 80s, horizontally mounted in an open air, single card system. This was on GPGPU computing. Due to the heatsink design, ZERO air is exhausted and its all left to be removed by the case.  My PC cards heat the case ambient up to 40+ even with 3x250mm, 5x240mm of fans removing heat. You will have to open air, just have to.

Tldr: Mining is doable on the 3 slot PC cards, but will be almost impossible to dual M cards within a case. The M cards are 2 slot and don't exhaust air at all.


Power delivery:
This is the major problem. My PC cards have 3x8pin for a max of 525W. These new M cards only have 2x8 pins for 375W max. Even with my moderate overclocks (focusing on power consumption rather than MAX POWA), I'm going over/hitting the power delivery limits of the PC cards at about ~400W from the wall per card [1050 core, mem 625 and undervolted]. AnandTech saw this in Furmark, the card was power throttled HEAVILY. Now imagine trying to scypt mine with decent clocks - its not going to happen.

Tldr: The power delivery on these cards LIMITS the performance of these cards and causes power throttling even on moderate computing load. Hence these cards are not appropriate for mining.

I'm more than happy with my 3 slot non Maltas, hopefully more stock is made. If I helped, small small small donations are appreciated and pay for good things

[computerparts]

You really should do more research so that you know what you're talking about when posting. There's a ton of misinformation you have so I'll only touch on one. You correlate Furmark and scrypt. First, there's no dual gpu card in existence that does not get throttled from running Furmark. Second, scrypt is more reliant on ram than it is on the core clock. Where as Furmark stresses the core more than anything.

[dogie]

You really should do more research so that you know what you're talking about when posting. There's a ton of misinformation you have so I'll only touch on one. You correlate Furmark and scrypt. First, there's no dual gpu card in existence that does not get throttled from running Furmark. Second, scrypt is more reliant on ram than it is on the core clock. Where as Furmark stresses the core more than anything.

Anand: FurMark ended up being harder on the 7990 than we expected. Both NVIDIA and AMD throttle it of course, but we’ve never seen it throttled so hard as on the 7990. The 7990 completely stalled at times and momentarily dropped to its medium power state (500MHz) while running FurMark. The results are still enlightening since we’re clearly hitting it peak power limits regardless, but it’s not a very good sustained load in this case."
http://anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/16

Just tried for arguments sake, furmark working fine maxing out on my two PC 7990s for the last 20 minutes. But anyway, this is not the source of my power consumption figures. I am comparing my cards, in hand, and their power consumption bitcoin and litecoin mining. They use way, way more than the PC cards can output and I'm not even pushing them hard [1050 core, 625 ram, undervolted core and ram]

Maybe you should do more research so that you know what you're talking about when posting, thanks.

[computerparts]

Tldr: The power delivery on these cards LIMITS the performance of these cards and causes power throttling even on moderate computing load. Hence these cards are not appropriate for mining.

You're joking right? Just because these cards hit their power limits on Furmark means they are not suitable for mining? Furmark is the most stressful test a gpu can ever face. SHA-256 does stress the gpu but it is strictly a computational load which is a big difference from the rendering load in Furmark. And scrypt comes nowhere near the stress Furmark is capable of.

Tldr: Mining is doable on the 3 slot PC cards, but will be almost impossible to dual M cards within a case. The M cards are 2 slot and don't exhaust air at all.

This is completely wrong. I'm not sure where you came up with the idea that it won't exhaust any air out of the back. The bracket is vented for a reason. But most serious miners are going to be running open air rack/crate mounted rigs anyway.

Power delivery:
This is the major problem. My PC cards have 3x8pin for a max of 525W. These new M cards only have 2x8 pins for 375W max. Even with my moderate overclocks (focusing on power consumption rather than MAX POWA), I'm going over/hitting the power delivery limits of the PC cards at about ~400W from the wall per card [1050 core, mem 625 and undervolted]. AnandTech saw this in Furmark, the card was power throttled HEAVILY. Now imagine trying to scypt mine with decent clocks - its not going to happen.

About the only thing you have right here are the pin inputs. You seem to be confusing TDP with power draw. TDP is heat measured in watts. They are not the same. Example: The Malta has a TDP of 375w but power draw at load can exceed 500w.

[dogie]

You're joking right? Just because these cards hit their power limits on Furmark means they are not suitable for mining? Furmark is the most stressful test a gpu can ever face. SHA-256 does stress the gpu but it is strictly a computational load which is a big difference from the rendering load in Furmark. And scrypt comes nowhere near the stress Furmark is capable of.

I'm actually basing my power consumption figures on those 7990s im mining on now - they are very very close to the furmark based consumption in those reviews - ie the cards are maxing. But then again my actual data is clearly superseded by your thin air evidence.

This is completely wrong. I'm not sure where you came up with the idea that it won't exhaust any air out of the back. The bracket is vented for a reason. But most serious miners are going to be running open air rack/crate mounted rigs anyway.

"For the 7990 however AMD has dropped the blowers entirely for a completely open air design. The tradeoff between the two being that while blowers are self-sustaining and ensure all hot air is expelled by the card – or at least half of the hot air in the case of half-blowers – open air coolers move more of the work to the chassis in exchange for generally lower noise levels.

At the same time this change does mean that the chassis/case used becomes more important than ever. Of the 375W of heat generated by the 7990, only a fraction of it will be kicked out via its vent; the rest will be dumped into the case"
http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/2

I think you can keep your magical fluid dynamics.

About the only thing you have right here are the pin inputs. You seem to be confusing TDP with power draw. TDP is heat measured in watts. They are not the same. Example: The Malta has a TDP of 375w but power draw at load can exceed 500w.

"On the power front their binning has enabled them to get a dual-GPU Tahiti card out at 375W. The 7990 is a 375W card...."
http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/16

"Maximum Power 375 W.
AMD buttons the Radeon HD 7990 up into a dual-slot card that only needs two eight-pin auxiliary power connectors to drive it. With that said, the card jams right up against the PCI-SIG’s electromechanical specification for one x16 slot and two eight-pin connectors: 375 W. "
http://www.tomshardware.co.uk/radeon-hd-7990-review-benchmark,review-32675-2.html

I'm very surprised for someone calling themselves 'computerparts' how uneducated you are, but at the same time the air of superiority you carry when you are plain wrong. In fact, the TDP is a great indicator of how much electricity the chip itself will use. Smaller effects keep the two being identical but they are very, very close.

Electrical energy is converted PURELY into heat energy - there is nothing else. If you think it consumes 500W and only generates 375W, where do you think that 125W of energy is going xD MAGIC.

TDP = maximum heat dissipation = maximum heat energy created/s = maximum electrical energy consumed/s = maximum power consumption. THAT ENGINEERING.

[computerparts]

I tried to educate you and this is what I get in return. So I see you not only need classes on thermodynamics but reading comprehension as well.

I'm actually basing my power consumption figures on those 7990s im mining on now - they are very very close to the furmark based consumption in those reviews - ie the cards are maxing. But then again my actual data is clearly superseded by your thin air evidence.

I never said anything about the cards not maxing. The fact is the gpu itself is rendering during furmark. It is NOT rendering during SHA-256 or scrypt. Do you even know what causes throttling? There is NOTHING that will make it throttle during computational loads.

At the same time this change does mean that the chassis/case used becomes more important than ever. Of the 375W of heat generated by the 7990, only a fraction of it will be kicked out via its vent; the rest will be dumped into the case"
http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/2

Again I never said anything about it not blowing air into the case. But it will exhaust air out of the back. It's not a big a deal as you're making it out to be.

"On the power front their binning has enabled them to get a dual-GPU Tahiti card out at 375W. The 7990 is a 375W card...."
http://www.anandtech.com/show/6915/amd-radeon-hd-7990-review-7990-gets-official/16

"Maximum Power 375 W.
AMD buttons the Radeon HD 7990 up into a dual-slot card that only needs two eight-pin auxiliary power connectors to drive it. With that said, the card jams right up against the PCI-SIG’s electromechanical specification for one x16 slot and two eight-pin connectors: 375 W. "
http://www.tomshardware.co.uk/radeon-hd-7990-review-benchmark,review-32675-2.html

First of all, don't ever quote anything from Tom's. Doing so will reduce your credibility. I knew you were going to use that quote from Anand. Shame on them for not clarifying. Look at the specs. See where it says Powertune/TDP? And what is that number? 375. They are not talking about the maximum power draw. They are talking about the efficiency as a result of the binning process. Do you know what binning is? In layman's terms, it's when chip manufacturers pick out the best yields and choose the chips with the tightest tolerances.

Electrical energy is converted PURELY into heat energy - there is nothing else. If you think it consumes 500W and only generates 375W, where do you think that 125W of energy is going xD MAGIC.

TDP = maximum heat dissipation = maximum heat energy created/s = maximum electrical energy consumed/s = maximum power consumption. THAT ENGINEERING.

I'm not even going to say how dumb you make yourself look here. If this were the case none of your electronics would work because according to you, all of the electrical energy a device is using is converted to heat. You're completely ignoring the law of conservation of energy. I'm glad the real world isn't based on your rules. If a device consumes 500w and only generates 375w of heat, that means it's using 125w of that energy to do what it's suppsed to do and the rest (375w) is wasted as heat.

[dogie]

I tried to educate you and this is what I get in return. So I see you not only need classes on thermodynamics but reading comprehension as well.

Masters in Engineering, thanks. How about you? Nope, didn't think so.

If a device consumes 500w and only generates 375w of heat, it means it's using that 125w to do what it's supposed to do and the rest (375w) is wasted in heat.

This is priceless. I'm actually going to put this quote up on my wall.

[Spendulus]

I tried to educate you and this is what I get in return. So I see you not only need classes on thermodynamics but reading comprehension as well.

Masters in Engineering, thanks. How about you? Nope, didn't think so.

If a device consumes 500w and only generates 375w of heat, it means it's using that 125w to do what it's supposed to do and the rest (375w) is wasted in heat.

This is priceless. I'm actually going to put this quote up on my wall.

A part of the wattage is converted into accelerating air from a standstill to design speed for cooling purposes.  I suspect this becomes quite substantial. 

Consider the case of a fan alone.  It generates some heat (minor) and useful work (Major).

I'd say both you guys had the amps in --> heat/work wrong.

LOL

[dogie]

I tried to educate you and this is what I get in return. So I see you not only need classes on thermodynamics but reading comprehension as well.

Masters in Engineering, thanks. How about you? Nope, didn't think so.

If a device consumes 500w and only generates 375w of heat, it means it's using that 125w to do what it's supposed to do and the rest (375w) is wasted in heat.

This is priceless. I'm actually going to put this quote up on my wall.

A part of the wattage is converted into accelerating air from a standstill to design speed for cooling purposes.  I suspect this becomes quite substantial. 

Consider the case of a fan alone.  It generates some heat (minor) and useful work (Major).

I'd say both you guys had the amps in --> heat/work wrong.

LOL

And where does the kinetic energy from the fan go? That's right, to heat. As soon as the air stops moving, its converted all its KE to more heat energy.

But no, a fan is not the same as a GPU.

[HellDiverUK]

So the short version of this is:

The 7990 can mine no problems, but can't run Furmark.

Good thread, OP.   

[melmo]

 OP is correct - computers in general (not just gpus) are almost 100% efficient in converting electricity to heat.

[dogie]

So the short version of this is:

The 7990 can mine no problems, but can't run Furmark.

Good thread, OP.   

Yes and no.

The 7990 from third parties [ie the 3 slot 525W version] CAN mine no problems as long as you have 1+ gap in-between.
The official 'Malta' 7990 in 2 slot and 375W CAN'T mine - too many heat and power limitations.

[BBQKorv]

So the short version of this is:

The 7990 can mine no problems, but can't run Furmark.

Good thread, OP.   

Yes and no.

The 7990 from third parties [ie the 3 slot 525W version] CAN mine no problems as long as you have 1+ gap in-between.
The official 'Malta' 7990 in 2 slot and 375W CAN'T mine - too many heat and power limitations.

I use those third party 3-slot 7990s for mining, and they do very well. I haven't tested Malta yet, but I can assume it will have issues mining. If you own a non-Malta 7990 just feel the thermals, you'll get trouble if that gets shrinked to 2 slots and to only 2 power connectors.

Furmark throttling is nothing in comparison to what scrypt mining or OC'd sha256 will do to the card. My mining temps and power draw is bigger in mining than in Furmark.

[Miner99er]

Why don't we just wait till a M***** F***** around here gets a Malta 7990, slaps CGminer on it, and see what the damn thing does?

Too much epenis waving in the air around here.

[dogie]

Why don't we just wait till a M***** F***** around here gets a Malta 7990, slaps CGminer on it, and see what the damn thing does?

Too much epenis waving in the air around here.

I'd rather wave it around and save someone $1000 of disappointment, time and dismay.

[computerparts]

I'm going to mine with 3 of them. OP has no clue what he's talking about.

[dogie]

I'm going to mine with 3 of them. OP has no clue what he's talking about.

xD PLEASE do, we will enjoy the spectacle of you trying to exhaust 1200W of heat from a case while getting 500MH a card due to throttling. Please post updates.

Self belief is only a positive attribute up to a point, at which it becomes a blinding detriment.

[computerparts]

I'm going to mine with 3 of them. OP has no clue what he's talking about.

xD PLEASE do, we will enjoy the spectacle of you trying to exhaust 1200W of heat from a case while getting 500MH a card due to throttling. Please post updates.

Self belief is only a positive attribute up to a point, at which it becomes a blinding detriment.

I never said I was going to stuff them in a case. But there is a case I can think of that has proven to handle that task so I'll glady take your challenge. Care to put some btc on it as well while we're at it?

[dogie]

I'm going to mine with 3 of them. OP has no clue what he's talking about.

xD PLEASE do, we will enjoy the spectacle of you trying to exhaust 1200W of heat from a case while getting 500MH a card due to throttling. Please post updates.

Self belief is only a positive attribute up to a point, at which it becomes a blinding detriment.

I never said I was going to stuff them in a case. But there is a case I can think of that has proven to handle that task so I'll glady take your challenge. Care to put some btc on it as well while we're at it?

No, because you're the only one who can verify the results and I don't trust you one bit. And oh look, you have a vested interest in one of the outcomes.

[Aggrophobia]

game package seems to be worth 400$