2x6870($300) VS 1x6970($300)

[newguy05]

will run everything at stock. which is better for mining? they cost about the same. Thanks

2x6870 ($300)

or

1x6970($300)

[jjiimm_64]

will run everything at stock. which is better for mining? they cost about the same. Thanks

2x6870 ($300)

or

1x6970($300)

if not for the fact that one deal uses 2 slots, and the other one.

6870 will get you about 290 Mh   that is 580 Mhsh
6970 is about                              400-410

[Enigma81]

290MH on a 5870?  Seriously?  I get over 430 from 5850s.

[ArtForz]

290MH on a 5870?  Seriously?  I get over 430 from 5850s.

*6*870. Probably stock clocks or a suboptimal miner with a very mild OC.
And 430Mh/s from 5850s? That's ~1GHz core. Wonder how long they'll last...

[Enigma81]

930 core.  under 70C.

[ArtForz]

930 core.  under 70C.

430Mh/s at 930 core on a 58*50*?
That'd be 335Mh/s stock. On a 5850.
Or 436Mh/s on a stock 5870.
So... why is everyone else reporting numbers *way* below that?

[bulanula]

930 core.  under 70C.

430Mh/s at 930 core on a 58*50*?
That'd be 335Mh/s stock. On a 5850.
Or 436Mh/s on a stock 5870.
So... why is everyone else reporting numbers *way* below that?

ArtForz, how do you calculate these formulas and stuff ?

I look and don't understand anything. LOL

How do you get the mhash/s value from the core and shaders the card has ?

[ArtForz]

930 core.  under 70C.

430Mh/s at 930 core on a 58*50*?
That'd be 335Mh/s stock. On a 5850.
Or 436Mh/s on a stock 5870.
So... why is everyone else reporting numbers *way* below that?

ArtForz, how do you calculate these formulas and stuff ?

I look and don't understand anything. LOL

How do you get the mhash/s value from the core and shaders the card has ?

It's rather simple to convert between cards of the same family, mining scales pretty much 100% with #shaders * clock.
430Mh/s / 930MHz / 1440 shaders = 0.000321087 hash/shaderclock
0.000321087 hash/shaderclock * 850 MHz = 272923.95 hash/shadersecond
272923.95 hash/shadersecond * 1600 shaders = 436678320 hash/sec.

so to convert, it's generally simply hashrateA / clockA / #shadersA * clockB * #shadersB

[Enigma81]

930 core.  under 70C.

430Mh/s at 930 core on a 58*50*?
That'd be 335Mh/s stock. On a 5850.
Or 436Mh/s on a stock 5870.
So... why is everyone else reporting numbers *way* below that?

Not sure why everyone else is so low - or why I'm so high.... Here's a screen-shot showing the Device Hardware ID's (5850), MSI Afterburner Settings, and Mining Results.

(EDIT)Hmm.. In taking that screen-shot, I see I'm running a bit warm today.. 74C.. Have to check on my fan.  Also, screenshot shows 427.xx Mhash/sec which was primarily due to me moving images around on the screen - my rate dropped by a few Mhash while I was doing that and taking the capture.  It's usually about 431.xx if I leave the machine alone.

[jjiimm_64]

snip

Yup..  looks like you have a 5870 there clocking away at the normal 430Mh at 930 clock.

[Enigma81]

Hmm.. You might be right, actually.. I remote-desktop into that machine.. maybe it got a 5870 stuck in it rather than the 5850 that I thought was in it..

Have to check when I'm over at the facility where that box lives later this afternoon..

[ArtForz]

snip

Yup..  looks like you have a 5870 there clocking away at the normal 430Mh at 930 clock.

Yeah, but the PCI device ID says it's supposed to be a 5850...
Honestly not sure WTF to make of that, all I get is "congratulations, you're the proud owner of a 5850 with 1600 enabled shaders."

[Enigma81]

Just ran GPU-Z.. 1440 shaders.. It's a 5850 like I thought.
http://www.techpowerup.com/gpuz/47rdp/

[jjiimm_64]

hmmm, interesting..

well,  it sure is hashing exactly like a 5870 would....  maybe a 5870 with a 5850 bios?  i dunno. 

if is look like a duck and quacks like a duck!

[ArtForz]

Just ran GPU-Z.. 1440 shaders.. It's a 5850 like I thought.
http://www.techpowerup.com/gpuz/47rdp/

Well, iirc GPU-Z shader # is simply based off a hardcoded table of device IDs, so that's no big help either.
Atm I'm out of ideas of how to figure out what is really going on there, just seems *very* odd that your 5850 is 11% faster than what everyone else is reporting, and 111% just happens to be very close to 1600/1440.

[jjiimm_64]

Yup, just call it a 5870 and move forward....  I have some 7970's here in a box, cant wait to get them home

[ArtForz]

Now, after massive thread derailment... back to OPs question.
stock vs. stock 2*6870 easily beats 6970. 2*~290 = ~580 vs. ~390 for a 6970.

[jjiimm_64]

Now, after massive thread derailment... back to OPs question.
stock vs. stock 2*6870 easily beats 6970. 2*~290 = ~580 vs. ~390 for a 6970.

agreed and as originally said, if slots are not at a premium

[newguy05]

thanks guys, i ordered 2x 6870. Hope they dont freeze my pc every 24 hours like my old 5970 did.