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are all A64's Multiplyer locked?

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to my knowledge, i read in a forum here, some arent.. but some also can be wireed unnlocked.
 
mista ting said:
are the multiplyer's on all A64's locked? because i only see people using the HTT thing to overclock im just wondering :)
The multiplier of any A64 is locked upwards (except for the über-expensive FX-series :-/
 
Basically you can take the multiplier down, but you can not rase it past factory settings. Example. Mine is set at 10x. I can clock it down to 9.5x, 9x, 8.5x, etc. I can not however take it up to 10.5x. To get around this we raise the FSB over 200 and lower the LDT setting from 5x to 4x (need to keep the HTT under 1000 or its usually unstable). Still with me?
 
hitechjb1 said:
1. CPU_frequency = HTT x CPU_multiplier

CPU mulitplier is CPU specific, some can be adjusted from below up to the stock multiplier of the CPU.
E.g. A64 754 3200+, stock 2GHz = 200x10, multiplier X10, X9, X8, X7, ....

CPU multiplier

The FX are unlocked. But the A64 754, 939 are unlocked up to the default stock multiplier.
E.g. for a A64 754 3200+, 2 GHz stock frequency, default multiplier is x10, so it is unlocked for x10, x9, x8, ....
This is good since one can still overclocking the HTT which is related to the HT system bus and the memory bus via their respective multipliers.

...


For details:
Overclocking setting for various bus frequencies
 
A64s do not have hardware multipliers. They use PowerNow! transitions to change clock. All A64s have startup and maximum multipliers set in the factory. No processor can be set to multiplier over the maximum because the chip checks internally for this and refuses to change to such a multiplier.

Regular A64s have startup = maximum so if you have a CPU with nominal 2000 MHz then startup = 10x and maximum = 10x. FXes have startup as for their nominal frequency and maximum set to 25x. So and FX53 at 2.4 GHz has startup of 12x and maximum of 25x. Mobile A64s have startup set to a value usually 4x or 5x and maximum is set according to their nominal.

This means all the chips are locked, only that FXes have a maximum set higher than regular A64s.


Also... saying "But the A64 754, 939 are unlocked up to the default stock multiplier" is not true. CPU will allows for such a multiplier but applications changing it must comply to VCO changing rules that prohibit some multipliers. For example a multiplier of 7x has VCO of 14x - you need a CPU with at least VCO 13x (that is a 2.6 GHz chip) to set multiplier of 7x. If an application sets the multiplier by direct transition, it will corrupt data and the system will become unstable!
 
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