VarDiff

VarDiff (Variable Difficulty) is a mechanism that automatically changes share difficulty to adapt the frequency of submitted shares to the computing power of an individual miner.

Miners connected to the same pool can have very different hashrates. One participant may operate a single low-power device, while another may operate a large mining farm. If both used exactly the same share difficulty, the number of results submitted by each worker could differ dramatically.

Why VarDiff Is Used

The primary purpose of VarDiff is to maintain a practical share submission rate. The pool needs enough results from each worker to track its work statistically, while avoiding an excessive number of network messages.

Miner Hashrate	Typical Adjustment	Goal
Low	Lower share difficulty	Receive shares frequently enough for tracking
High	Higher share difficulty	Avoid excessive result submissions

How Difficulty Changes

The pool monitors how frequently a worker submits shares. If results arrive too frequently, the pool can increase the difficulty. If shares arrive too infrequently, the difficulty can be reduced.

VarDiff therefore attempts to keep the average interval between shares close to a target value defined by the pool.

VarDiff vs. Network Difficulty

VarDiff does not change the blockchain’s network difficulty. It operates only at the level of pool-assigned jobs.

Network difficulty determines how difficult it is to find a complete block. Share difficulty determines how frequently the pool receives intermediate results from miners.

Changing VarDiff therefore does not mean that a cryptocurrency has become harder or easier to mine. It changes only the pool’s internal work-accounting mechanism.

Practical Importance

A properly configured VarDiff mechanism helps reduce unnecessary network traffic while providing enough data to estimate worker hashrate. Inappropriate parameters can result in excessive message traffic, shares being submitted too rarely, or unnecessary load on pool infrastructure.