Disclaimer: This guide is for miners who know how to overclock and understand the possible dangers. I will not take responsability if anything happens to you're mining rig while following the steps in this guide.USE AT YOUR'E OWN RISKIntroduction:I just entered the game of LTC Mining and when all my cards where up and running I tried to find the maximum speed on both my HD 7850 and HD 7950 cards.
Because I could not find any systematic guide to help me reach that goal, and had to browse various forums and scrape together information, I decided to make my own guide.
THERE ARE TONS OF WAYS TO OVERCLOCK YOU'RE GRAPHICS CARD, these are just the methods I used to get the maximum out of my cards.
The HD 7850 guide is in the second post and takes a different approach then the HD 7950 guide.
What do you need to begin with:Download and install the latest versions of:
GUIMiner-scrypt https://bitcointalk.org/index.php?topic=150331.0AMD Drivers http://support.amd.com/us/gpudownload/Pages/index.aspxSapphire Trixx https://www.sapphireselectclub.com/ssc/trixx/trixx.aspxGPU-z http://www.techpowerup.com/downloads/2221/TechPowerUp_GPU-Z_v0.6.9.htmlHD 7950:
To start:
- Launch GUIMiner-scrypt
- Launch GPU-z
- Launch Sapphire Trixx
GUIMiner-Scrypt1. Start GUIMiner-Scrypt
2. Make sure you configure the GUIMiner-scrypt that it works with you're mining pool.
3. Select the standard
GPU Defaults for 7950 (high usage)
- Worksize 256
- Intensity: 20
- thread concurrency: 21712
- Vectors 1
- GPU threads 1
4. Press start and look at the kH/s, write this down.
Sapphire-Trixx
1. Start Sapphire-Trixx
2. Go to Overclocking tab
GPU-z
1. Start GPU-z
2. Go to the Sensors tab
Tweaking
Step 1: Find your maximum stable memory clock speed at stock memory voltage.a) Open Sapphire Trixx and bump up to memory clock from the stock 1250 Mhz to 1400 Mhz and press Apply.
b) Press start in GUIMiner-scrypt
c) Look at GPU-z Sensors tab and keep an eye on the temperatures (I keep them under 85°C, others say 80 °C)
d) After 2 minutes press stop in GUIMiner-scrypt
e) If the AMD driver did not crash, move the memory clock up by 50Mhz
f) Repeat b), c), d) and e) untill you're AMD driver crashes.
h) If you're AMD driver crashed you need to reboot you're graphics card otherwise GUIMiner-scrypt will give you low hash rates.
Start --> Search programs and files --> Device Manager --> Display Adapters
Right click on AMD Radeon HD 7900 Series --> Disable
Wait 30 seconds
Right click on AMD Radeon HD 7900 Series --> Enable
Restart Sapphire Trixx
Restart GUIMiner-Scrypt
Restart GPU-z
g) Then downclock 50 Mhz from the amount you got when the AMD driver crashed
Example: Driver crashes at 1650 Mhz --> 1650 Mhz - 50 Mhz = 1600 Mhz
Example: Maximum stable memory clock at stock voltage = 1600 mhz
Step 2 :
Calculate the desired GPU clock speed with this simple formula:core clock/maximum stable memory clock = 0.65
Example: core clock/1600 = 0.65 --> core clock = 0.65 * 1600 --> core clock = 1040
Step 3: In Sapphire Trixx set you're VDDC at 1.25v and Board Power Limit to 20Step 4: Enter the value calculated in step 2 for the core clock in Sapphire Trixx and press start in GUIMiner-Scrypt.Step 5: Fine tune the core clock by increasing/decreasing the core clock with 1mhz steps untill you see the highest value of kH/s in GUIMiner-Scrypt.Example:
1039/1600 --> 601 kH/s
1040/1600 --> 605 kH/s
1041/1600 --> 603 kH/s
Step 6: Run the system for hours. If it crashes, lower the memory clock settings by another 25 or 50 Mhz and repeat steps 2 to 5.Step 7: (ONLY IF STABLE) Lower VDDC each time with steps off 0.010 volts to find minimum stable voltage settings untill the card crashes or won't start up in GUIMiner-Scrypt.
Then run for hours, if it crashes, bump up the vCore by 0.010, repeat until fully stableIf this helped you, feel free to donate any small amount of LTC to:
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