February 19, 2014

Hashrate Hunt: XFX R9 280X Black Edition

A few weeks ago I, like many other before me, got hooked by mining. In its essence, it's all about calculating hashes really, REALLY fash and hoping to find a small enough hash. If you do, you get money!

The problem was that my old graphics card, GTX 560 Ti, was slow. It pumped about 150 kilohashes per second. Now, to give some contrast, recently released graphics cards tend to push over 700 kilohashes per second. So, I decided to update to a bit more modern graphics card (I mean, I was going to need a new one anyway, now I had one more reason!). After two days of online window-shopping, I came across a viable choice: XFX R9 280X Black Edition. I had read that 280X has a good bang-for-buck ratio, boosting out 750 Kh / s. So, I ordered the card, feeling really enthusiastic.

Come last friday, I unbox the card, swap it with the old one, install drivers and launch cgminer...

...and boy was I disappointed. 550 Kh / s.

I crawled through some cryptocurrency forums and subreddit, and decided to try out sgminer. Result? 580 Kh / s. Sigh. I mean, I was "happy" that it was about four times faster than my old card, but I was still disappointed as I hoped more.

The next few days, I tried a lot of stuff: flashing modified BIOS, overclocking, revising the cooling system, adjusting launch parameters... Nothing seemed to do the trick. 580 Kh /s was the magic barrier. Feeling utterly defeated, I was browsing the forums once again, sipping cold coffee, listening to the crappy, slow graphics card going "WWWWWWWWWWWWWZZZZZZZZZZZZZ" under the desk... And then, I found some discussions about newer Sapphire cards having this weird "feature" where the BIOS throttles the graphics card if it overheats. Hmm... The BIOS version in question was a tad older than the one in my card, so it could be true for my card as well.

At this point, let me recap the clock values of my card. The card is factory-overclocked to 1100 MHz core clock and 1650 MHz memory clock. Many other cards available have a lot smaller clocks, but they still hash faster.

Anyway, I came across a post that claimed that the magic values would be 1020 MHz for core and 1500 MHz for memory. Well, why not? Seems a bit counter-intuitive, but what the hell...

... 670 Kh / s. 670 Kh / s! Wow. By underclocking the card, I got over 17% more hashing speed! I even tweaked it a bit more, setting the core clock to 1028 MHz, and it gave a tad over 680 Kh / s. Awesome.

The problem seems to be abou throttling with this card. Now, if I set the memory clock to, say, 1520 MHz, the speed will instantly drop to ~500 Kh / s. What about 1490 MHz? it drops to 650 Kh / s. It seems that I can't touch these values anymore at all. Bummer.

Well, it's a victory for now. But I'm not done yet. It MUST to go over 700! In the meantime, here's my batch file for those who are interested:

sgminer.exe -o <address_here> -u <user.worker> -p <pass> --lookup-gap 2 -g 2 -I 13 --thread-concurrency 8193 -w 256 --gpu-memclock 1500,1500 --gpu-engine 1028,1028 --gpu-powertune -20,-20 --expiry 1 --scantime 1 --queue 0 --no-submit-stale --gpu-threads 2 --gpu-dyninterval 7

Thanks for reading through, and if you found this useful, feel free to donate some coins :)

DogeCoin (DOGE): DG5PDSTiZd8KPxTgb8uSgBS4XRKdD31dcc
AuroraCoin (AUR): ALtibmHLSg3j54P8xGs8pYFKdooKAZjNyL

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