Ninjastic
PostEdited versionsQuotes to this post
Post
Topic
Board Mining
Re: To people who are technically versed: Will the HD 7xxx series be good at mining?
by
Coolhwip
on 03/07/2011, 16:02:19 UTC
Quote from: KarlSpaat on July 03, 2011, 09:05:47 AM
Can someone please verify that the AMD HD7000 Cards won't have the Int32 Right Rotate Operation (very useful for SHA-256).

I can't find it in any rumor about the upcoming HD7000 series.

And you won't find confirmation anywhere because it has not been removed, v_alignbit_b32 is still there.
Here is a partial dump of the Southern Island's instruction set: http://forum.beyond3d.com/showpost.php?p=1561886&postcount=365

Under vector instructions, there is v_alignbit_b32

Quote
http://www.hardwareboard.eu/topnews/geruchte-zur-radeon-hd-7000-serie-kommt-definitiv-noch-2011-in-28nm-update-8-release-monat-bekannt-379/

This homepage (german) says, that the upcoming HD7xxx chip will have 3200 Shader Cores and about 6.08 TFlop/s. But unless AMD releases official informations, we should be careful with this informations.

https://en.bitcoin.it/wiki/Why_a_GPU_mines_faster_than_a_CPU
And finally in this wiki there is an explanation why ATI is better for mining than Nvidia. If the HD7000 really has 6,08 TFlops and does support INT32 Right Rotate, we will see about 750 MHash/s.

Why do i make this prediction?
Simply a not overclocked HD5850 has 250 MHash/s with about 2 TFlop/s. A GTX480 reaches 105 MHash/s with 1.4 TFlop/s. The INT32 RR Operation gives ATI an advantage of 1.9 for SHA-256 hashing. Together with the higher Peak Performance of the HD5850, the 5850 should be about 2.6x faster than a GTX480, which is nearly true.

I know the HD7000 cards will use a newer architecture similar to NVIDIA, but Mining performance seems to depend linear to the peak performance of a video card. The reason why ati cards are more efficient seems to be just the INT32 Right Rotate Operation, which can be performed in one operation on ATI cards, but needs 3 operations on Nvidia cards. So it's very important to know wether the HD7000 support this operation in order to predict the Hashrate.
The specs posted on that site are pure speculation. No one knows the actual specs of the new cards, but we do know the underlying architecture and we know (via the instruction set dump from the drivers) that AMD's GCN (Graphics Core Next) does support the INT32 Right Rotate Operation.

Quote from: fitty on July 03, 2011, 03:34:16 PM
Quote from: Coolhwip on July 03, 2011, 11:20:06 AM
Quote from: rograz
...show me a 6970 pulling 445MH/s at 1ghz core like the 5870 does.
Here:
...cut image out...

I have it at only 950core/1375Memory doing an average of 460+MH/s (values fluctuate between 457.8, 460.5, 468.7). Still, a 5870 is far more efficient at mining since the GPU is smaller by half a billion transistors, it has half the ram clocked at a lower speed and at lower voltage plus the PCB is less complex (less layers).

WTF.

What SDK? Can you post all the flags you're using? That's insane.

Besides using Vista, I've never been able to get that on my 6970s let alone on that clock. I have to push it to 1ghz to get even close and I'm still 20 mh/s short. Getting 460 with aggression at 7?

I'm extremely confused. I've tried a zillion combos on win7 and linux I don't understand how you get that speed. Could Vista really boost it by that much?
No, Vista is largely irrelevant. I just put that in there for full disclosure. My performance is achieved through the various kernel tweaks posted on the forums. These tweaks appear to have a greater benefit on the VLIW4 architecture of the HD69xx (Cayman) cards than the VLIW5 architecture of the HD5K (Cypress) family.