My initial Radeon HD 7970 mining benchmarks

[DiabloD3]

Chapter 4.16 of the AMD OpenCL programming guide has some optimization guidelines for GCN. This snippet explains why my vectorization experiment didn't help performance:

... "Vectorization is no longer needed, nor desirable." ...

Oh well, back to the drawing board! 

I'm not going to believe that until I can prove it. Also, mining kernels are very abnormal for how kernels function, it is very much not a typical kernel. I'm glad they updated the programming guide for GCN though, its very useful for intermediate OpenCL programmers.

[1713863918]

1713863918

[DiabloD3]

So much for AMD's "Fold and mine faster than ever with AMD App Acceleration powered by the unprecedented 28nm GCN Architecture."

There is nothing false about their statement.  It looks like the 7970 IS the fasted mining card.  AMD made no claims in terms of efficiency (MH/W or MH/$).

I mean it is like buying the fastest sports car and then saying the company lied because it costs more and has worse gas mileage than a Honda Civic.

This. 7970 is the fastest GPGPU bar the 7990 coming out RSN. AMD hasn't misadvertised anything.

[DiabloD3]

I've just found a forum post where someone reported stable performance with 0.939V core voltage at stock speeds. Stock voltage is 1.170V so if we ignore the other components of the card that would mean a ~20% power reduction (or more, due to reduced temps), and therefore a 20% efficiency gain as well (bringing the MH/J up from the 2.2-2.5 range to the 2.75-3.125 range). They also report a 7C temp drop which should let me reduce the fan speed from an annoying 60% to sub-50%, which is barely audible against the other case fans.

But this is all just theory until someone actually measures it, so off to find a BIOS that actually lets me lower the core voltage!

Actually power decreases at the square of voltage change.  A 20% undervolt is huge.  If true one would expect more like a 35% drop in power.  Now let me hedge that by saying dropping core voltage doesn't drop mem voltage so it is more like a 35% drop in CORE ONLY power.  Still overall power savings should be >20% for a 20% undervolt. 

If true that could make an undervolted 7970 (especially if someone can figure out how to undervolt the memory something I haven't been able to do on 5970) a hybrid between FPGA and GPU.

Power usage in Mhz is linear (ie, 500 to 1000 mhz will double power usage), but power usage in voltage is squared (using 100 watt at 1 volt? It will use about 150 watts at 1.25 volt).

[DiabloD3]

I'll go add official 8 and 16 wide support in a bit, should be useful on, say, AVX if you manually enable CPU mining in the code. SDK 2.6's cpu compiler apparently has gotten a lot better from what I've heard.

I'll be watching the repository then It should almost definitely help with more modern CPUs and Larrabee/Intel MIC.

I just pushed a new commit. You can do vector layouts instead of the old bitmasks. So instead of -v 18, you do -v 1,1, instead of -v 36, you do -v 4, instead of -v 40, you do -v 4,4, instead of -v 4, you do -v 2,2, etc.

[DeathAndTaxes]

I've just found a forum post where someone reported stable performance with 0.939V core voltage at stock speeds. Stock voltage is 1.170V so if we ignore the other components of the card that would mean a ~20% power reduction (or more, due to reduced temps), and therefore a 20% efficiency gain as well (bringing the MH/J up from the 2.2-2.5 range to the 2.75-3.125 range). They also report a 7C temp drop which should let me reduce the fan speed from an annoying 60% to sub-50%, which is barely audible against the other case fans.

But this is all just theory until someone actually measures it, so off to find a BIOS that actually lets me lower the core voltage!

Actually power decreases at the square of voltage change.  A 20% undervolt is huge.  If true one would expect more like a 35% drop in power.  Now let me hedge that by saying dropping core voltage doesn't drop mem voltage so it is more like a 35% drop in CORE ONLY power.  Still overall power savings should be >20% for a 20% undervolt. 

If true that could make an undervolted 7970 (especially if someone can figure out how to undervolt the memory something I haven't been able to do on 5970) a hybrid between FPGA and GPU.

Power usage in Mhz is linear (ie, 500 to 1000 mhz will double power usage), but power usage in voltage is squared (using 100 watt at 1 volt? It will use about 150 watts at 1.25 volt).

Yes and he indicated he UNDERVOLTED by 20%.  0.8%^2 = ~0.65 or 35% reduction in core power at the same clock (assuming the same clock is possible w/ 20% undervolt) which is why I was impressed.  A 20% undervolt is kinda hard to believe.

[DiabloD3]

Yes and he indicated he UNDERVOLTED by 20%.  0.8%^2 = ~0.65 or 35% reduction in core power at the same clock (assuming the same clock is possible w/ 20% undervolt) which is why I was impressed.  A 20% undervolt is kinda hard to believe.

Yeah, but you traded top speed for efficiency, which lowers efficiency in the dollar sense (ie, mhash/$).

[1onevvolf]

Managed to undervolt without flashing the BIOS. Just needed to enable the core voltage option in MSI's Afterburner software and that's it!

At the moment I'm running overclocked getting 670MH/s @ 1125/975 AND undervolted from 1175mV to 1112mV, for a 37W reduction from stock settings down to 230W power draw for the card at this speed. The fan is also down to a more bearable 50%

So with these stable settings the efficiency figure is 2.91 MH/J. This is smack in the middle of my estimated figures from earlier. I'm sure that lower core frequencies will allow for even bigger undervoltages.

The funny thing is that the card would actually run stable at 1040mV with a 197W draw as long as the only thing it was doing was mining which is 3.4MH/J. But fire up a game and it would crash after a short while. Maybe this is due to the power management features turning things on and off as was mentioned earlier in this thread? Anyway, it seems that head-less mining boxes using these cards have room for more efficiency gains.

Tomorrow I'll measure some more data points to get a better idea of what these characteristic curves look like.

P.S. I dunno if its a bargain for mining or not but I'm having a lot of fun with this card so far and mining quite a few bitcoins in the process

[project10]

Thanks for providing these numbers for those who are still waiting on their cards, or are considering picking some up.

Not bad for an AMD PR flack!

[rjk]

3.4MH/J

wow, nice! It working with a bitcoin miner, and crashing with a game is certainly because the bitcoin miner ignores large portions of the die, causing them to use little or no power since they are idle. This is why it may have been stable at that dramatic of an underclock.

[blandead]

That's amazing, considering how much better this card is with games alone, sounds like a very good all around card. I'm sure the prices will drop significantly when the fab can spit out more cards.

[sadpandatech]

The funny thing is that the card would actually run stable at 1040mV with a 197W draw as long as the only thing it was doing was mining which is 3.4MH/J. But fire up a game and it would crash after a short while. Maybe this is due to the power management features turning things on and off as was mentioned earlier in this thread? Anyway, it seems that head-less mining boxes using these cards have room for more efficiency gains.

It's mostly due to the games utilizing the card's ram. Which of course needs more juice.

Awesome results though thus far. I'll have to go back and poke at my lil 5830's a bit but I don't believe they undervolt nearly as well as what these 7970's are doing thus far!  That in itself is promising.

Thanks for sharing your data with us, m8.

cheers

[HolodeckJizzmopper]

Got my Diamond 7970 in today.

Running latest DiabloD3 (https://bitcointalk.org/index.php?topic=1721.0), I'm getting ~593Mhash/s @ 1000mhz with default settings. Have not started tweaking yet.

Fan running at 70% has the card at ~71C

[Hexadecibel]

I'm running my Sapphire 7970@1125 with temps at 74 with 55% fan.

 

getting 668Mh/s

I've got about $6,000 at my disposal and I'm trying to decide if I want to buy 8 more 7970's or buy the bitcoins outright.
Anyone here willing to sell me 1,000 bitcoins for 6 grand?

[tonto]

It's probably the location of my room (stale air), but I'm getting 87C temps at stock (1000Mhz black edition).
 
I even have it in a large Corsair 800D which has pretty good air flow...
 
I'm also contemplating liquid cooling (for other reasons) but there are water blocks out for the 7970 so that would help if I decide to go that route.

[DeathAndTaxes]

I've got about $6,000 at my disposal and I'm trying to decide if I want to buy 8 more 7970's or buy the bitcoins outright.

That is a no brainer.  Buy 20 used 5970 and get 40 GPUs.

[Hexadecibel]

 B-b-bu-but 7970s :*(

I'm having a hard time finding a good source for 5970's.

I was under the impression from reading in these forums that an under-volted 7970 is at least on par with a 5970 or a little bit better.

But wouldn't just buying them be easier?
.

[Fiyasko]

B-b-bu-but 7970s :*(

I'm having a hard time finding a good source for 5970's.

I was under the impression from reading in these forums that an under-volted 7970 is at least on par with a 5970 or a little bit better.

But wouldn't just buying them be easier?
.

Buy FPGA's Some of us gamers still want those cards for gaming xD
Or buy some used 5970's

[1onevvolf]

I'm also contemplating liquid cooling (for other reasons) but there are water blocks out for the 7970 so that would help if I decide to go that route.

Yeah I'm thinking about that as well for my next upgrade. With a waterblock and the right bracket these cards fit in a single slot and overclock so much better. And best of all no more annoying fan!

[DiabloD3]

Got my Diamond 7970 in today.

Running latest DiabloD3 (https://bitcointalk.org/index.php?topic=1721.0), I'm getting ~593Mhash/s @ 1000mhz with default settings. Have not started tweaking yet.

Fan running at 70% has the card at ~71C

Woah, and I said its probably possible for >600 on stock clocks. So close.

[fasti]

Can people post room temperatures also with gpu and %fan. As room temp has pretty huge impact on %fan.