Effect of speed
In general, increasing wire speed can increase abrasive interaction frequency and may reduce cutting force per abrasive contact. Some SiC-related research notes cutting force decreases as wire speed increases under its tested conditions.
However, higher speed can also increase heat, coolant demand, wheel wear, and sensitivity to imbalance or joint quality.
Practical adjustment
When surface quality is poor, speed should not be changed alone. Check feed rate, wire dullness, coolant flow, debris removal, and workpiece support.
For fragile crystals, it is often safer to change parameters gradually and document the relationship between speed, roughness, and edge condition.