FSB: Integrated into Chip - What does it mean?

[Garet Jax]

Hello all,

I am probably going to be buying new MB, Chip and RAM soon. I am trying to make sure I buy things that are all compatible with each other. I see a lot of variations in FSBs in RAM. I see Hypertransport, 800, 1600 or 2000 for FSBs in MB and I see "Integrated into Chip" for FSB for CPUs. Can you please help me start to understand this stuff? Thanks.

 

[MDE]

The FSB is technically the link between the RAM (or northbridge) and CPU. Because of the Athlon 64's integrated memory controller, what would be the traditional FSB is integrated onto the CPU. HyperTransport is what the CPU uses to connect to the chipset, so people have been substituting the HT speed for the FSB.

 

[Garet Jax]

I thought the FSB was the link between all components (HD, PCI and AGP slots, RAM, Chip) on the MB.

OK. So assuming I buy an A64 chip (socket 754 or socket 939) and a corresponding MB, what rating on the RAM would I want to get to match the best (assuming no OC). Does it depend on the Chip or the MB at all?

 

[ChineseDemocracyGNR]

The Athlon 64 supports DDR400 and slower. So you should get DDR400 memory (PC3200). You can run higher speeds by overclocking.

All the boards can support this speed, with the exception of the ECS 755-A. This was fixed with the ECS 755-A2, and is caused by design problems on the original board.

Socket 939 boards support dual-channel, socket 754 boards don't.

To give you a better understanding of what the FSB is, check out the system architecture overview of a K7 platform:
http://www.sis.com/products/sis748_benefits.htm
FSB is the speed used to connect the processor to the northbridge which has the memory controller.

Compare that to a K8 platform:
http://www.sis.com/products/sis755_benefits.htm
HyperTransport is used to connect the processor to the northbridge, but the memory controller is not on the northbridge.

 

[imported_Hi]

Integrated FSB is only on AMD64 since the memory controller is integrated in the cpu it runs at the processors speed