Question regarding Pentium 4 CPU and bus

[pc2-brazil]

Homework Statement

Why is it impossible for Pentium 4 to work in a 32-bit PCI bus without loosing any functionality? After all, other computers with a 64-bit data bus can do transfers of 32, 16 and even 8 bits wide.

Homework Equations

The Attempt at a Solution

I'm not sure what loss of functionality is being referred to here.
Does it have to do with the fact that Pentium 4 has 36 address lines? Or that PCI has a relatively low clock rate (up to 66 MHz)?
I don't have any idea.

Thank you in advance.

 

[KataKoniK]

Dear forum post author,

Thank you for your question. In order to understand why it is impossible for the Pentium 4 to work in a 32-bit PCI bus without losing any functionality, we need to first understand the differences between a 32-bit PCI bus and a 64-bit data bus.

A 32-bit PCI bus has a total of 32 address lines, which means it can address up to 4GB of memory. On the other hand, a 64-bit data bus has a total of 64 address lines, which allows it to address up to 16 exabytes of memory. This is a significant difference in memory addressing capabilities.

Additionally, the Pentium 4 processor has 36 address lines, which means it can address up to 64GB of memory. This is more than what a 32-bit PCI bus can handle, but significantly less than what a 64-bit data bus can handle. This means that the Pentium 4 processor would not be able to fully utilize the memory addressing capabilities of a 64-bit data bus if it were to be used in a 32-bit PCI bus. This would result in a loss of functionality, as the processor would not be able to access all the available memory.

Furthermore, the clock rates of PCI and the Pentium 4 processor are not compatible. PCI has a maximum clock rate of 66 MHz, while the Pentium 4 processor has a much higher clock rate. This would result in the processor being underutilized and not able to perform at its full potential, leading to a loss of functionality.

In conclusion, the Pentium 4 processor is not compatible with a 32-bit PCI bus due to its higher memory addressing capabilities and clock rate. This would result in a loss of functionality and therefore, it is not possible for the Pentium 4 to work in a 32-bit PCI bus without any loss of functionality. I hope this explanation helps to answer your question. If you have any further doubts, please feel free to ask. Thank you.