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Im thinking to upgrade my pc and switch to AMD.

Im looking at the cpus and mobos.. and i see that the 64's (san diego?) have 1ghz FSB.. then the motherboards are selling also with 1ghz FSB..
But the memory supported by these motherboards are pc3200 wich that means 800FSB in dual channel right?..
So wouldn't memory bottleneck the CPU/Mobo and the overclocking?..
May be i got the concepts wrong... can anyone explain me what to look for?

Thanks
 

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Quote:


Originally Posted by telovoyagarcar

Im thinking to upgrade my pc and switch to AMD.

Im looking at the cpus and mobos.. and i see that the 64's (san diego?) have 1ghz FSB.. then the motherboards are selling also with 1ghz FSB..
But the memory supported by these motherboards are pc3200 wich that means 800FSB in dual channel right?..
So wouldn't memory bottleneck the CPU/Mobo and the overclocking?..
May be i got the concepts wrong... can anyone explain me what to look for?

Thanks

You're really confused. The 1ghz that you're referring to isn't a typical frontside bus, it's the HyperTransport Bus. The new AMDs don't have a typical frontside bus because the memory controller is on the cpu itself, not on the northbridge. PC3200 is 200 mhz and it what the stock speeds are based off of. (cpu mult X 200 = processor speed)
 

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Branching off sccr's post:

Your FSB is called your HTT, but they aren't the same, as sccr has told you. Your FSB (HTT) has it's own multiplier (HTT multiplier, not to be confused with your regular CPU multiplier. 939 boards have both).

As an example, we'll use your observation: a motherboard is said to support 1000 MHz HTT. This means that if your FSB (HTT) is set at 200 MHz, it can be multiplied by the HTT multiplier by 5 to get 1000 MHz. If you raise your HTT over 200 MHz your motherboard will become unstable since it will be over 1000 MHz, so you will have to change the HTT multiplier to 4 to get 800 MHz. Same thing here: if you have a 250 MHz HTT you will multiply it using your HTT multiplier to get 1000 MHz. If you again raise your HTT past 250 MHz you will have to lower your multiplier to three.

As I said earlier, the CPU multiplier still applies as well; you will still use it to multiply your FSB to obtain your CPU frequency.

Sorry if that was a bit of a large explanation, but I'm really, really tired, so it's hard to be quick and smart at the same time lol
 

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the HTT or hypertransport does nothing for performance if it's set higher than 1000 or lower. It just needs to be set with a "stable" HTT multi so the system will boot. Its really simple, just understand that overclocking the HTT does nothing for performance, and should be kept under 1000.
It cant hurt anything either if you set it too high or too low. Your system will not boot up if it's set improperly..ez fix
 

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Hmm, I've heard it can be unstable if set below 750-800 MHz. This true? I'd think it would be, otherwise everyone would just set their multiplier to 1 then haha.
 

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It mostly depends on the board...
some boards are stable all the way up to 1200mhz. Some are unstable just over 1000. Some boards prefer the lower numbers, while others like higher...
It just boils down to the board, but the HTT and the HTT multi is the easiest thing to set for stability..
 

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The LDT multiplyer (memory) relative to the HTT is a bit confusing at first.
HTT and CPU ... as it is increased the LDT would be adjusted to maintain the RAM's stability, in part, as do the RAM timings and vdimm require additional attention if you maintain a 1:1 CPU:RAM speeds.
Basically the
HTTxLDT=1000 or
200x5=1000
201-250 use an LDT of 4x
251-333 use 3x
The LDT voltage may also require increses.

A RAM divider is required when the RAM can not maintain a 1:1 ratio to the CPU when the HTT is increased beyond the RAM's ability to match the speed.
 

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I'd like to note that I did notice a slight(boy was it slight) difference in benchmarks with a 700mhz-800mhz vs. a 900mhz-1000mhz FSB.

Find it took about 50 more mhz on the CPU OC to make up the difference.

So I think it's not 100% accurate when people say "It makes no difference".
 
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