Quote from: Tejsei3 on April 27, 2013, 01:47:56 PM

Quote from: pizza on April 26, 2013, 08:53:11 PM

Quote from: FullLife on April 18, 2013, 02:34:59 AM

Quote from: Tejsei3 on April 07, 2013, 06:14:37 AM

Looking for help to improve kH/s/W.

Here's my setup:
MSI Z68MA-ED55 (B3) motherboard
Intel G530 processor
4GB DDR3 1066 RAM
7950 Sapphire 100352-2L (purchased March 2013, voltage unlocked!)
16X-16X riser cable
Corsair TX750W power supply
AMD 13.1 drivers
AMD SDK 2.8
cgminer 2.11.3 (-I 20, --tc 22400 -w 256 -g 1 -l 1)
Sapphire Trixx

Best settings: 925/1250/.962V 560kH/s 3.29 kH/s/W.

Given high electricity cost my goal is to maximize kH/s/W.

My current best setup is 925/1250 at 0.962V for 560 kH/s at 170W or 3.29 kH/s/W, after many hours of systematically mapping gpu clock (850-1250), memclock (1250-1750), and gpu v (0.900-1.250). I've had the rig up to 740 kH/s stable (1225/1750/1.250V) but at 345W or 2.14 kH/s/W the efficiency just isn't there (would be great for a free power situation!).

Looking for advice from the experts on what to do next to improve my efficiency.

Thanks,

Tejsei

Wow, that's an absolutely fantastic efficiency! I saw a tiny improvement (~ 5 Kh/s) changing the thread concurrency from 22400 to 16384. See if that helps you at all.

I just ran those settings excellent!! Anybody know what to tweak to get it up to maybe 620kh without upping the voltage to an extremely high level? I messed around with everything I can't seem to go any higher.

Try 1050/1650/1.075 I'm seeing 640 kH/s at 235 W per card or 2.72 kH/J.

Even though this is less energy efficient, it is still more profitable given the ratio of electricity expense to litecoin value.

In case it helps anyone else, here is how I have it figured out in a spreadsheet:

=(hashrate*mining100USD/100)-(powerInW*electricityExpenseInUSD/kWh*24/1000)

mining100USD is the USD earned by mining 24h with 100 kH/s. To get this number, look up dustcoin.com/mining and enter "100" in the scrypt hashrate field, then in the Revenue field it will tell you how many coins/day earned. This is mining100LTC. Convert this to mining100USD by multiplying by the LTCUSD conversion rate, such as $2.5/LTC.

So here's an example:

Profitability = (640 kH/s * 1.108 USD/100kH/s/d / 100) - (235W * 0.10 $/kWh * 24h / 1000W/kW) = $7.09 - $0.56 = $6.52

Using this you can compare different hashrate/power setups and see which is more profitable, taking into account your electricity expense.

Hope this helps.

I never thought to look at it like that. This is great, thanks!