Originally posted by: smokedturkey
get the 2500+ and those low voltages are not going to cut it at 2ghz, that is the default
voltage at low mhz. Remember, these are laptop cpu's.
Get CrystalCPUID and you can change the multiplier and voltage from windows.
This is really more simple than people are making it.
smokedturkey, I realise this. The thing is that the XP-Ms come in a number of flavours and I'm wondering which flavour would be likely to overclock the most.
For example, I have a 2500+ XP-M running at a default 1867 MHz and 1.45V. Since it is the same core as the desktop Bartons, I obviously expect that this chip will go much higher (can't yet test this myself). There is also a 2400+ that runs at a default of 1800 MHz at 1.35V. There is also a 2600+ that runs at 2000 MHz at 1.45V. And there is a 2800+ XP-M that runs at 2133 MHz at 1.65V. I have verified this in AMD technical documents.
I also know that other variables are the week of manufacture and the stepping code of the chips.
When looking to buy a XP-M on the internet, it is typically difficault to pin down all the details of the chips that are offered for sale. Therefore, I am wondering if an approach based solely on the default voltage and default clock frequency of chips offered for sale would yield clues as to the likely overclockability of a given chip.
N.B.A word of warning - AMD assigns the same PR rating to chips with varying core voltage, therefore the PR rating alone is not sufficient to identify the characteristics of a particular chip.
If so, I am wondering which of the flavours of XP-M I have mentioned would,
ceteris paribus (week of manufacture and stepping), be expected to have the best overclocking potential.
The 2400+ I mentioned manages to squeeze 1800 MHz out of 1.35V, which seems impressive. The 2600+ gets an extra 200 MHz at a cost of an extra 0.1V. Do people think it is possible to generalise, based only on these facts, which flavour would give the best results?
There may be other factors that people are aware of. For example, it would not surprise me if certain flavours of XP-M were not produced at all by AMD until they had reached a certain stage of maturity in their manufacturing process. Thus, when buying a particular flavour, one might know that the week of manufacture could not possibly be before a given date. Such analysis might also apply to stepping codes.
And finally, people might know, or be able to surmise, AMD's policy on selecting particular batches of chips for a given PR rating. It could be, for example, that it is so incredibly difficult to produce chips capable of 1800 MHz at 1.35V that AMD selects only the best chips for this classification, even though they might not make so much money per chip by doing so. Alternatively, AMD might choose to operate by selling all its best chips as desktop 3200+ versions.
I would be grateful for any insights people have on this.