We’re asked weekly about this so we felt it was best to explain:
Higher difficulty DOES indeed decrease the amount of disk reads, but the amount of them still stays very low. It does not increase HDD wear or how much the disk spins.
For example, you have a 18 TB drive loaded fully with plots. This means 176 k32 plots. On every signage point (every 9 seconds), you have 34% chance that at least one plot will pass the plot filter and the farmer will be required to do a quality lookup, which is approximately 10 reads.
By only doing quality lookups, you use 10*0.34/9=0.38 IOPS. A one 18 TB drive fully loaded with plots produces ONE proof per 49 seconds. One full proof lookup takes 64 reads, which means that you will use additional 64/49 = 1.3 IOPS. Modern 7,200 RPM drives have the IOPS capacity of 80, 5,400 RPM HDDs have 60. Worst Case (18 TB 5,400 RPM drive) , 1 difficulty will take only 0.38+1.3=1.68 IOPS, which is only 1.68/60=2.8% of the disk’s IOPS capacity.
And don’t forget that this is the worst case. With 10x the difficulty, this number will be 0.13+0.38=0.51%. 100 difficulty 0.013+0.38=0.39%, etc.
“But what about disk sleep?” The drive will wake up when it passes the plot filter no matter the difficulty since the quality lookup is made regardless of the proof being found or not.
It is possible to set your difficulty higher, the standard farmer does not currently support this feature.
Low difficulty allows for accurate statistics tracking which is really important to both small and large farmers to accurately judge their farm and diagnose any issues. If there is a problem with your farmer you will know about it faster. This also allows for them to receive a relatively fair percentage of each block instead of having a high variance between them. A fixed difficulty also eliminates some of the possible exploits that play off variable difficulty.
If we’re comparing bandwidth usage between Flexfarmer at 1 difficulty versus the normal old client you’ll see that bandwidth usage is cut by more than 90% to under 4 Kb/s for a 95TB Farm. RAM usage is cut down to under 200mb on average from gigabytes. Likely energy usage is cut a similar amount. Energy usage, internet bandwidth usage, processor usage, and memory usage are much higher normally than Flexpool using Flexfarmer. Your equipment will likely last a lot longer using Flexfarmer with Flexpool because there is a lot less stress on it and your power bill will be lower. You’ll also be able to use your computer for other things while running Flexfarmer in the background as Flexfarmer only uses minimal resources.