Mamba wrote on 2024-09-19, 14:11:
ElectroSoldier wrote on 2024-09-19, 13:55:No were not.
People pick up the SL5XL chips thinking they can SMP with them because theyre P3 1400 CPUs. […]
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Mamba wrote on 2024-09-19, 13:46:Yes,
We are always talking about S, when it comes to SMP. […]
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Yes,
We are always talking about S, when it comes to SMP.
This is the point of the request.
The motherboard seems to be not ok with two S in SMP.
That is why I am asking for a modded bios or for someone able to look at it.
No were not.
People pick up the SL5XL chips thinking they can SMP with them because theyre P3 1400 CPUs.
After making sure the chips can smp then you should be looking into does the board work with coppermine cpus.
Which we already have the answer to... so you should be looking at the chips can smp.
Its the next logical step.
I have a MS-9105 that happily works with a pair of SL5XL....
All P-IIIS can do SMP.
Happily...
The main differences that enable SMP support in processors like the Pentium III-S compared to standard desktop versions lie in a few key areas of the chips design and implementation
1. Multi-Processor Interconnect Support
SMP capable processors have additional logic and hardware support for managing communication between multiple processors. This includes the ability to coordinate cache coherency between processors in a multi-socket system, ensuring that each CPU has an accurate view of the system memory and caches.
The processors use a system bus (FSB) that allows multiple CPUs to share the same memory and I/O subsystems. SMP-capable processors are designed with circuitry to properly handle bus arbitration and allow both CPUs to communicate with the chipset and each other efficiently.
2. APIC (Advanced Programmable Interrupt Controller)
SMP processors generally include a local APIC (Advanced Programmable Interrupt Controller) that allows the CPU to handle and route interrupts in a multi-processor system. The APIC is crucial for directing interrupts to the correct processor in an SMP system, ensuring that system-wide tasks can be shared between CPUs without conflicts.
In single-processor CPUs (which do not support SMP), the APIC may be simplified or absent, as there is no need to manage multiple processors.
3. Microcode and Firmware Differences
SMP-capable CPUs often include specific microcode and firmware-level optimizations that allow them to function in dual-processor configurations. These instructions control how the processor interacts with the system's memory, interrupts, and other processors.
This includes support for cache coherency protocols like MESI (Modified, Exclusive, Shared, Invalid), which ensure that each processor in the system has the correct and up-to-date version of any data in its caches.
4. Processor Validation and Testing for SMP
CPUs intended for SMP configurations typically undergo more rigorous testing to ensure that they can function properly in multi-processor environments. This includes validation for reliability, stability, and compatibility with multiple CPUs sharing resources like memory and I/O.
Even if two CPUs are physically similar (like a Pentium III and Pentium III-S), only those that pass this validation process will have SMP capabilities enabled.
5. Cache Differences
In the case of the Pentium III-S Tualatin processors, there’s also a difference in the L2 cache size. The Pentium III-S processors feature a larger L2 cache (512 KB), which is beneficial in multi-processor systems. This larger cache allows the processor to handle more data locally without having to communicate as much over the system bus, which can improve performance in multi-processor configurations.
However, the larger cache size itself is not the primary enabler of SMP support. It is mainly a performance enhancement that helps in multi-CPU scenarios.
The "S" in Pentium III-S stands for server, and Intel specifically designated these processors for multi-processor servers and workstations. This designation is often more than just a technical difference — it's a matter of positioning. Processors intended for single-processor use are typically not marketed or validated for multi-processor setups, even if they share many of the same physical characteristics.
VIA has always played fast and loose with its chipsets, I have no doubt they built it so people can do exactly what you are doing with it. The use it sees will mean it will probably never need any of the differences between the desktop and server models.
The 694D was a popular board at the time, it was cheap and available which is how I ended up with one. If what you want is possible then the net would be awash with people doing it.
2cpu.com, a site that seems to have been lost to time, might have been cached by the wayback machine. It was always a good place to chat with people who used dualies.
