To increase the amount of virtual memory go to Control Panel > System > Advanced > Performance > Settings > Advanced > Virtual Memory Change > Custom Size > adjust as needed. 2 times your physical RAM is a good minimum and 3 times your physical memory in MB is good for your maximum.
The three different types of lava differ in composition and flow rate. Rhyolitic lava is the slowest moving type of lava, since it has a high viscosity due to a high silica concentration. Basaltic lava is the fastest moving lava because of its low viscosity resulting from a low silica content.
The main composition types are mafic, which are lavas rich in iron and magnesium, while being low in silica; intermediate, which are lavas with medium amounts of iron, magnesium, and silica; and felsic, which are lavas that have the highest silica and lowest magnesium concentration.