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I'm trying to upgrade my AMD processor to a better model, my motherboard specs say the processor has to be 89 watts or less and supports a bus speed of up to 2000 Mhz. The processors I'm looking at ARE 89 watts but the bus speed range anywhere from 2200-3000. My question is, is it safe to have a processor with a higher bus speed than my motherboard specs say? If not, then I won't have any other choice but to get a better motherboard, which I really don't want to do.

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Just check the motherboard compatibility table. –  David Schwartz Jun 20 '12 at 0:07
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All modern AMD processors use HyperTransport. The processor will simply operate at a slower bus speed. HyperTransport is backwards compatible and will properly handle devices with different speeds. From page 6 of http://www.hypertransport.org/docs/wp/HT_System_Design.pdf:

When devices supporting different clock speed and link widths are connected together, the HyperTransport technology protocol layer ensures the bus works correctly without the need for special I/O drivers.

I don't see why installing such a processor would be unsafe, as long as the processor and motherboard sockets are compatible.

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For one thing, if the motherboard cannot provide the supply voltage the CPU needs. –  David Schwartz Jun 20 '12 at 6:03
    
@DavidSchwartz: The supply voltage is always the same for a given socket. Wattage is a more important factor, and the processor to be selected will be within the 89-watt limit. –  DragonLord Jun 20 '12 at 6:18
    
Do you have a citation that says that AMD doesn't add new VID entries when they release new CPUs? I know Intel does. And I can't find any reference that documents AMD's policy. –  David Schwartz Jun 20 '12 at 6:26
    
I'm not familiar with this type of compatibility problem--can you explain it to me? –  DragonLord Jun 20 '12 at 15:26
    
When AMD or Intel release new CPUs, they often run at different voltage levels from previous CPUs. They often also have different requirements for things like how the voltage level is changed (how quickly, how much current must be supplied while it's changing, and so on). Motherboard VRMs must meet these new requirements to support new CPUs. A motherboard can't be designed to meet VRM requirements that don't exist at the time the motherboard is made, so if a CPU has new VID/VRM requirements, a motherboard can't support it without hardware changes. –  David Schwartz Jun 20 '12 at 20:55
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