When installing processors with mixed stepping levels in a server, which guidelines must be followed?

When installing processors with mixed stepping levels in a server, it's essential that the processors have the same cache size set. This requirement arises because mismatched cache sizes can lead to compatibility issues and inconsistent performance. In a multi-processor system, the operating system and applications rely on consistent architecture across processors to effectively manage workloads and memory. Having the same cache size ensures that all processors can handle data in a uniform manner, which is crucial for maintaining stability and performance within the server.

The reason this guideline is important is that it helps maintain a balanced system, allowing the server to utilize all processors effectively without running into issues related to cache coherence, where the data stored in different caches may become inconsistent. This could result in degraded performance or even system crashes if the processors are attempting to access data differently due to cache discrepancies.

Other considerations in a multi-processor environment can include factors like frequency and feature sets, but these are secondary to ensuring the cache sizes match. Compatibility at this fundamental level helps ensure the system runs smoothly and efficiently, enabling the processors to work together as intended.