Vardiff
Vardiff is variable share difficulty: the pool tunes it to each worker's hashrate so shares arrive at a comfortable rate.
How vardiff works
A share is an easier job than a real block, and the pool sets its difficulty itself. A weak ASIC gets light shares so the stats do not sit silent for hours, a powerful one gets heavy shares so it does not flood the server with thousands of tiny answers per second. One goal: a steady stream of shares from every worker.
The tuning happens on the fly. A new miner connects, the pool starts at a default difficulty, watches the response rate, and dials it in within a few minutes. Switch the firmware profile and vardiff readjusts on its own.
Income does not change. A heavy share earns proportionally more credit than a light one, so the daily total is the same at any difficulty. Only the granularity of the stats changes: with heavy shares the pool's hashrate chart jumps around more, and that is normal.
Manual control exists too: many pools accept a suffix like d=65536 in the worker password. It makes sense on proxies and on big farms where the automation takes longer to settle than you would like. For a single ASIC the best choice is to leave it alone.
The short version
| What gets tuned | share difficulty to match the worker's hashrate |
| Why | a steady flow of shares without overloading the server |
| Effect on income | none, credit is proportional to difficulty |
| What changes | the granularity of the pool chart |
| Manual control | the d= suffix in the worker password, if the pool supports it |
What is useful to know here
The pool's numbers lie for the first minutes after connecting: vardiff is still hunting for the level. Do not judge hashrate by that window.
A jumpy chart on a steady miner is most often just heavy shares, not a problem. Look at the daily average.
After switching firmware profiles, give the pool half an hour to readjust before comparing numbers before and after.
On a proxy, set the difficulty by hand if the automation keeps swinging: one steady figure for the whole farm behaves more predictably.
An example from the stats
A 200 TH/s ASIC and an old 13 TH/s one mine on the same pool. Vardiff gave the first a difficulty many times higher, and both send shares every few seconds. In money each earns exactly its hashrate: one heavy share from the first is worth the same credit as a stack of light ones from the second.
Related terms
Where to go next on the site
Numbers
Hardware
- ASIC Miner knowledge base
Questions and answers
Can you earn more on low difficulty
No, credit is proportional to share difficulty. Light shares give you a pretty, busy chart and the same daily total.
Why does my share difficulty keep jumping
The pool keeps tuning: after a profile change, a disconnect, or idle time, vardiff hunts for the level again. It settles within a few minutes.
What does d=65536 in the worker password mean
A request to pin difficulty at that value. Not every pool honors it, and it is mostly for proxies and large farms.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .