HD 6770

[KWH]

http://www.guru3d.com/articles_pages/his_radeon_6770_iceqx_turbo_crossfire_review,1.html  Crossfire for mining, I wouldn't. If you don't crossfire you will still need a dummy plug.

[ATC777]

I'm gonna shut down, remove my GTX-580 and try the 6770 solo to see what happens... 

[ATC777]

Ok, that works... Now GUIMiner shows me a new GPU device named "Juniper"...

But... It's only pushing about 127.5MH/sec???  

The mining hardware comparison page said this thing should hit over 220MH/s.... which is the only reason I bought the damn thing... If it's only capable of 127 then it was a total waste of money and I'll need to go return it immediately.

This is actually slower than my GTX-580...

[creativex]

6770's will do over 200 with mild overclocks. I operate two Sapphire 6770's w/ bASIC-MINING and both exceed 200MH/s. One does 1020 core @ stock voltage. Just fiddle with them awhile till you find the right overclock. You want them right on the edge of instability.

[ATC777]

6770's will do over 200 with mild overclocks. I operate two Sapphire 6770's and both exceed 200MH/s. One does 1020 core @ stock voltage. Just fiddle with them awhile till you find the right overclock. You want them right on the edge of instability.

Oh, ok... I thought those stats on the page were for right out of the box, not over-clocked.

Should I use Afterburner?

[creativex]

I haven't done the math in awhile, but I believe they're still the most efficient cards I run and the fact that they only use one PCIe connector is a plus. The only downside is that they offer relatively low hashes while using a PCIe slot on your mobo. A slot that could be taken by a 79xx, 59xx, or 58xx.

[ATC777]

I've never really been into over-clocking... I've always left my hardware at manufacturer settings for a few reasons:

1) long lifespan and resale value
2) I'm a DirectX dev and need to test on "stock" hardware -- which most people are running
3) system stability
4) etc, etc...

So this is a new challenge for me. Should I tamper with Afterburner as my mining app is running, or is it necessary to shut it down, change settings and try again?

Also, could you tell me how you have yours clocked so I can copy your profile and test it?

[ATC777]

Just guessing off the top of my head I'm thinking:

920Mhz for core clock
1300MHz for mem clock

 Sound like a good starting point?

EDIT ::

920 & 1300 got me up to 140MH/sec, which is almost even with the "stock" GTX-580... So I guess I just keep on tweaking it upward...

This does make me kind of nervous though lol, cuz I'm a n00b to overclocking. How do I know the "red zone" at which I could damage my hardware?

[crazyates]

Underclock the snot out of the RAM for lower temps and zero affect on performance.

[ATC777]

I just committed a major boo-boo... crashed the card... Thank God I didn't scorch it lol...  really... don't... know what I'm doing... lol

[creativex]

You will likely have to unlock afterburner with the EULA config mod. After that do as suggested and lower memory clocks as low as possible(start with 600). This lowers power consumption and reduces heat. This can usually be done without exiting the mining program, just check it before you leave. One of my cards does 970 and the other does 1010 happily.

[ATC777]

Ok, it makes sense to me why I should lower the RAM speed... Bitcoin mining uses SHA-256 and we barely even use our GPUs' RAM (quite the opposite with Litecoin/Scrypt) -- so lowering clock speed on the RAM will keep my card cooler and more efficient...

But... What settings do I need on my core? What's the "danger zone"?

[ATC777]

Uh oh... GUIMiner no longer detects my GPU... 

[creativex]

That's card specific and can vary wildly from card to card. That said, it's probably safe to assume they'll do 950ish. 6770s don't get very hot at all either.

Edit: The latest versions of BFGMiner are very nice, I tend to use it for BTC mining and have CGMiner set up for LTC Mining.

[ATC777]

Yeah, something is very wrong here... "Juniper" (the HD 6770) is no longer a detected device and I can't use it anymore... It was all working fine until I tampered with clock settings and my card crashed...

However, I'm using the card now and it does display and seems to be working ok.... WTF...

EDIT::

I ran a D3D11 sample (rendering rotating triangle) with my game engine to ensure the card still works for 3D/gaming... worked fine... Ran ArmA II: Reinforcements for confirmation and it also worked fine. So it doesn't appear that the card has been damaged at all. I also put everything back to factory clock settings. But it's still gone as far as GUIMiner, cgminer or any other mining app is concerned...

[ATC777]

Ok, I re-installed AMD Catalyst package with .NET 4.0 support and now GUIMiner can detect "Juniper" (the HD 6770) again... Whew... Glad to have that fixed. Now I can get back to trying to over-clock at get > 200MH/sec performance...

Still open to suggestions on core clock speed and mem clock speed. Also, how about fan speed? Should I just leave it on "auto"?

[ATC777]

Maxed out the core clock @ 960MHz and the best it can do is 145Mh/sec... 

[ssateneth]

Maxed out the core clock @ 960MHz and the best it can do is 145Mh/sec...  

Because you're using the newest AMD APP, which is probably 2.7. 2.7 and 2.6 blow HORRIBLY for anything that doesn't absolutely require it (see radeon 7000 series). Use 2.1, 2.4, or 2.5 (I recommend 2.1, but you won't be able to use it on that driver. I think the newest driver that supports 2.1 is 12.3, but you should still probably use 11.12 or 12.1).

Uninstall the entire thing, delete amdocl64.dll, amdoclcl64.dll, and OpenCL.dll from C:\windows\system32 and amdocl.dll, amdoclcl.dll, and OpenCL.dll from C:\windows\SysWOW64. For whatever reason, amd app and opencl aren't properly uninstalled when you uninstall the driver.

Download and install 11.12. Link is here. http://support.amd.com/us/gpudownload/windows/previous/11/Pages/radeon.aspx?os=Windows%20Vista%20-%2064-Bit%20Edition&rev=11.12
Driver is mandatory as well as the amd app. Catalyst control center not necessary at all. Reboot for funsies.

Recommended to install SDK 2.1 as well, but you only need to install ONE THING from the package. Unfortunately I can't find a link on amd's site. You can either download and install the only package you need from my dropbox here: https://dl.dropbox.com/u/9768004/ATIStreamSDK_dev.msi or you can google for ati-stream-sdk-v2.1-vista-win7-64.exe and extract contents and navigate to Packages\Apps\ATIStreamSDK_Dev_win764a\ATIStreamSDK_dev.msi. This will create a second openCL platform called "ATI Stream" that many have found a little faster than 2.4/2.5 (I believe 2.5 comes with driver 11.12). Note: Most miners will NOT find the ATI Stream opencl platform unless AMD APP is also installed. Also, ATI Stream -must- be installed after AMD APP is installed.

After you install ATI Stream, you should be able to mine at proper speeds. You should get something like 195 mhash on a stock speed 6770. 1GHz would push about 230 mhash. Make sure you select the proper platform with your miners settings. With CGminer or BFGMiner, this is with the "gpu-platform" argument, followed by a number. 0 is the first platform, 1 is the second platform, etc.

Make sure you are using the phatk (or phatk2 if you are using phoenix) kernel, BFI_INT if using something other than CGMiner/BFGMiner, worksize of 128, and vectors enabled or set to 2 (depending on miner). Also it is recommended to set memory low, usually in the area of 160-190MHz depending on core speeds; the optimum ratio is close to a 5:1 core speed to memory speed. It takes some fiddling around, but you will see much lower temperatures and likely higher mhash than stock memory speeds.

[ATC777]

Thank you!!!!!!!!!!!!!!!!!1111!!!11!one!!11elleven!!!!! 

 

That's a bit too much work for me to do tonight, but I will definitely take a crack at it (prob tomorrow morning)!

Anyhow... I'm running this card with cgminer right now mining some Litecoin, and it's actually running more than 2x's faster than the GTX-580. I know Litecoin uses Scrypt and it's a different ballgame, so could anyone explain why it's performing so much better for LTC mining? And would over-clocking the card's memory speed it up for Litecoin?

Also... Is it safe to tweak clock settings while your GPU is mining?

[ssateneth]

Most cards will play nice with clock changing when there is a load on it. Some are temperamental, some damaged ones may throw a fit too. None of it with permanently damage a card though. Worst case your computer will freeze.