OpenSimWorld is the directory of 3D Virtual Worlds based on OpenSimulator and connected through the HyperGrid. Learn More

The difference between Xengine and Yengine...
Yengine has premptive multitasking, xengine does not.
This solves the lsl function problem of llSleep(n); Which could not run on Xengine the same way. On Xengine using llSleep would use one of the cpu's threads and place it in sleep mode. Yengine, simply places a sleep command into a wait queue and keeps the cpu thread available for more processing of other scrips. Xengine is also slower because it translate script to c# language, then uses .net compiler to generate it. Once a script is loaded into Xengine the memory from it cannot be recovered even if the script ends. Yengine scripts recover the ram memory when a script ends, so it can be used by other things for example more visitors to your sim.
Xengine does not follow a true AOS (algebraic operating system) and will evaulate sequences to the wrong boolean expression, Yengine follows AOS to the letter, and will always evaluate expressions mathematically correctly.
Yengine is a modified derivative of XMREngine created by dreamnation and avination. It is faster, uses memory and cpu threads much better than xengine, and thanks to ubit umarov, it is now more stable than Xengine, and all the bugs have been eradicated, that were found.
So you can keep using the outdated broke Xengine, thinking you have gold. But as a professional programmer I realize the average person doesn't understand the importance of memory management, memory leaks, and thread lockup. So it's rather ludicrous for me to waste my time trying to explain why something is better to people who have no concept of professional programming fundamentals. I suppose I should put on my armor for when the attacks from idiots start rolling in...