A64 basics & processor guide

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Some basic information about A64 systems. Unlike Intel P4 systems which have the memory controller on the northbridge, A64's have the controller built right into the CPU.

http://www.cpuid.org/reviews/K8/index.php

A64 architecture


P4 architecture


A64 systems also use a different type of link for connecting integrated circuits. It's called HyperTransport or HT for short. It was previously known as Lightning Data Transfer or LDT. To learn more, visit the HyperTransport Consortium website.

The HyperTransport frequency (HTT) is similar to (but not the same as) the classic FSB, in that the CPU uses this frequency to generate its own internal clock.

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A64's also use memory dividers, just like Intel systems. You are always running a divider on an A64 system because the memory controller is on the CPU. And there is no performance penalty using any divider, as long as you maintain the same memory and CPU speeds.

Here is a divider table courtesy of Oskar Wu at DFI. He used an oscilloscope to check all the multipliers from 4 to 12.

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Maximizing HyperTransport

For best performance, you should be running at your board's maximum available HyperTransport speed. The basic formula is:

HTT (FSB) X HT multiplier (often called LDT in BIOS) = HyperTransport speed. The multiplier is often listed as a frequency. 1000MHz = 5x, 800MHz = 4x, etc.

If your board's maximum HT speed is 1000MHz and you have HTT at 250, then the multiplier should be set to 4x. 250 X 4 = 1000.

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Here's a good guide on A64 architecture, with tips on overclocking.

Link

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A basic overclocking guide can be found here.

A slightly more detailed A64 overclocking guide can be found here.

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Here are some useful links:

Desktop processor quick reference guide

Processor road map

A64 processor drivers and utilities

X2 dual-core processor drivers and utilities

Revision guide for A64 & Opteron processors

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How to read information on an AMD chip

AMD identification guide

Another AMD identification guide

AMD pricing list

Tech Report's processor decoder ring

A64 overclocking database (Socket 939 CPU's)

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Warranty FAQ's

Three (3) Year Processor In A Box (PIB) Limited Warranty

The following is from AMD's website: Link

AMD's Limited Processor Warranty does not cover non-boxed products purchased from resellers.

AMD only provides a warranty on its line of boxed processors.

Q: If I have a non-boxed product, who do I contact to determine if my problem is covered by the warranty?

A: Contact the company from which you originally bought your computer system or contact the system manufacturer. If your system was built by an OEM, please address your issue directly to that OEM for resolution. You can also consult the warranty documentation that accompanied your computer system for specific warranty terms and conditions. DO NOT contact AMD.

Q: The reseller from which I bought a system that contains an AMD processor informs me that my warranty has expired. Does AMD provide a warranty extension period for the processor?

A: No. AMD DOES NOT cover products purchased from reseller and DOES NOT provide any extensions to the warranty period as outlined in the documentation which came with your computer system.
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Limited warranty on OEM chips bought directly from AMD:

AMD's warranty on (non-boxed) processors extends only to customers who purchased products DIRECTLY FROM AMD and does not cover products purchased from resellers. You should direct any warranty inquiries to the supplier from whom you purchased this product. Link

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Thermal & electrical specs for 8th generation AMD processors (pdf file)

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There is nothing wrong with using a half-multiplier like 10.5 or 9.5. But when you use one, your RAM is not running as fast as you think it is. If you look at the divider table above, you'll see that half-multis often share the same divider as the next highest whole multi. For example, 11.5X200 (2300) and 12X200 (2400) both use 12 (with DRAM frequency set at 200MHz in BIOS). So, to calculate your real memory speed at 11.5X200, you have to do this:

11.5 X 200 = 2300MHz
2300MHz divided by 12 (RAM divider) = 191.67 (real memory speed)

AMD has never officially recognized half-multipliers. But motherboard makers put them in anyway to give users more options.

If you're not good at math, there's a nice utility for calculating your memory speed. You can download it here.

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The Tech Report has updated its CPU decoder ring.

Link

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Hardware Secrets has a brief article explaining the differences among the various cores.

Link