Crypto mining with LHR cards - the T-Rex dual mining effect

Crypto mining is something I read about but have never played with. I've read about how it works and how NVidia implemented an LHR limited hash rate to reduce the utility of their graphics cards for mining.  

The T-Rex project recently came out with a new version that bypasses much of the LHR by using the graphics card to mine two currencies at the same time. This lets you mine both currencies with transaction rates below the rate limit.

NiceHash QuickMiner / Excavator

This is my default miner that is easy to set up and easy to run with no installation.  It gives you good results with no custom setup required.  A single ethash miner running on my NVidia RTX 3080 TI generates about 52MH/s

Sample payout 

The right way to do a comparison is to compare hash rates at the same time and not BTC/24 hours across two different times.  We should run two rigs at the same time using two different configurations.  I only have one graphics card so I used two different time windows.  

This graph comes from the NiceHash mining rig statistics dashboard and shows my Quick Minder zero-config ethash versus a T-Rex dual mining combo of ethash and Raven.

Payout comparisons can be risky because of market volatility.  I picked two days next to each other with a possibly false assumption that the market hadn't moved much from one day to the next.

T-Rex Dual Mining

T-Rex dual-mining generates about 1/3 more than a single miner in my unscientific experiment. I first fed the standard Etherium miner into my NiceHash account and then a T-Rex Driven dual miner in order to get a feel for the difference dual mining could make.  The dual mining rig shows up as unmanaged in the NiceHash rig manager

Hash Rates

kapow and ethash run about 29-32 MH/s each, resulting in a unified average of 60MH/s.  

Earning Rates

I ran each configuration for 12 across two days.  The runs are at different times of the day.  Their legitimacy for comparison is suspect but good enough for writing a blog article. Each time window represents 4 hours of mining, too small a window for a confident comparison.

November 6 - one currency
  • 1168 BTC
  • 1134 BTC
  • 1106 BTC
November 7 - dual mining - two currencies
  • 1598 BTC
  • 1733 BTC
  • 1634 BTC

NBMiner 39.7 - partial LHR unlocking

Hash Rates

As a third approach, I used NiceHash Minder and upgraded NBMiner to version 39.7. I copied the new NBMiner into the NiceHash Miner plugins directory. The default NBMiner 3.95 currently bundled with NiceHash was replaced with 39.7 that includes a hash unlock. The setup instructions can be seen in this video.  

I was able to achieve 75-80 MH/s with minor tuning. Sample Output.

[18:43:43] INFO - ethash - New job:, ID: 5332fda1, DIFF: 509.5M
[18:43:45] INFO - ================== [nbminer v39.7] Summary 2021-11-08 18:43:45 ===================
[18:43:45] INFO - |ID|Device|Hashrate|Accept|Reject|Inv|Powr|CTmp|MTmp|Fan|CClk|GMClk|MUtl|Eff/Watt|
[18:43:45] INFO - | 0|3080ti| 84.30 M|    33|     2|  0| 294|  64|  88| 73|1560|10051| 100| 286.8 K|
[18:43:45] INFO - |------------------+------+------+---+----+--------------------------------------|
[18:43:45] INFO - |    Total: 84.30 M|    33|     2|  0| 294| Uptime:  0D 00:06:01        CPU:  2% |
[18:43:45] INFO - ==================================================================================
[18:45:45] INFO - ================== [nbminer v39.7] Summary 2021-11-08 18:45:45 ===================
[18:45:45] INFO - |ID|Device|Hashrate|Accept|Reject|Inv|Powr|CTmp|MTmp|Fan|CClk|GMClk|MUtl|Eff/Watt|
[18:45:45] INFO - | 0|3080ti| 82.77 M|    49|     2|  0| 294|  63|  88| 73|1665|10051| 100| 281.5 K|
[18:45:45] INFO - |------------------+------+------+---+----+--------------------------------------|
[18:45:45] INFO - |    Total: 82.77 M|    49|     2|  0| 294| Uptime:  0D 00:08:01        CPU:  2% |
[18:45:45] INFO - ==================================================================================
[18:47:15] INFO - ================== [nbminer v39.7] Summary 2021-11-08 18:47:15 ===================
[18:47:15] INFO - |ID|Device|Hashrate|Accept|Reject|Inv|Powr|CTmp|MTmp|Fan|CClk|GMClk|MUtl|Eff/Watt|
[18:47:15] INFO - | 0|3080ti| 80.89 M|    52|     3|  0| 293|  64|  88| 73|1695|10051| 100| 276.1 K|
[18:47:15] INFO - |------------------+------+------+---+----+--------------------------------------|
[18:47:15] INFO - |    Total: 80.89 M|    52|     3|  0| 293| Uptime:  0D 00:09:31        CPU:  4% |
[18:47:15] INFO - ==================================================================================

Earning Rates

The earning rate for NBMiner 39.7 was virtually identical to t-rex dual currency mining. These runs were right after the others
  1. 1652 BTC
  2. <tbd>

Setup for noobs

Sign up for NiceHash and runthe NiceHash QuickMiner 

NiceHash QuickMiner is a zero-install mining package that includes mining software and a pseudo-crypto wallet. It is very easy to set up and gives you something to play with. No system settings are required.  Nicehash uses standard miners under the hood, all of which will be rate-limited by NVIDIAs LHR.  The simplicity of setup and collection makes this the obvious route for the person who doesn't want to do a lot of maintenance or cobble together parts. 

NiceHash pays out to your NiceHash wallet 6 times per day.  You can transfer your NiceHash balance to a standard wallet at any time.

I eventually ran the QuickMiner install which gave me a launch window.

Feeding your NiceHash account with T-Rex

You can feed your NiceHash account from other mining packages by pointing them at your NiceHash virtual wallet and by using their Stratum generators. I followed the steps shown in this well done YouTube video 

The T-Rex mining package has added the ability to deploy two different miners, and their DAGs, to the same video card.  You can T-Rex as a zip file and run it as a zero-install. 
  1. Download their software
  2. Unpack the zip
  3. Edit the appropriate LHR Unlock dual bat file 
  4. Point it at the QuickHash Stratum
  5. Replace the account number in the bat files with your NiceHash wallet id
  6. Run the bat file
  7. Look at your NiceHash mining rig dashboard

Setup for NiceHash Miner and NBMinder

Sign up for NiceHash and run the QuickMiner to verify your account.

Download and install the NiceHash Miner.  Windows users will have to make some antivirus changes to use NiceHash.  Run the default mode to verify it works. Youll need to update the NBMinder version that NiceHash Miner expects to be using.  Watch the video for easy instructions.


Custom tuning can make a noticeable difference. The common wisdom on the internet is that memory overclocking will provide more gains than CPU tuning. Gigabyte provides AORUS as a tuning tool. My settings ended up being.

  • CPU 1710 (0 additional)
  • Memory +1600
  • Power target 80%
  • Temp Target 81C
The memory temperature ran bout 86 degrees

Files used as part of testing

  1. NiceHashQuickMinerV961.exe: A standalone executable downloaded as part of the demonstration NiceHash page.
  2. NiceHashQuickMinerInstaller.exe: Installs QuickMiner somewhere other than Downloads.  Provides a launch tool. Useful if you are going to want to lanch QuickMiner from something other than the demo download link.
  3. A version of t-rex that supports dual minters
  4. nhm_windows_3.0.6.9.exe: NiceHash Miner install package.  Supports multiple third party plugins.  Install as few as possible. You will probably only install or enable NBMinder and Excavator.
  5. A version of NBMiner that opens up the LHR cards to more performance


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