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Whats TDP

bigjimmyauk can you please delete or edit down that ridiculously large quote you made of my post . . . there is simply no need for its existence! :D
 
It's a loose guide to the heat wattage the chip will need dissipated at stock frequency and voltage. It's not very accurate, you want to know the stock wattage really but this is dependent on chip vid and probably other things, so TDP is the best value going. Important features are scaling linearly with increased frequency and quadratically with voltage (suspect this is now vcore + qpi, for 775 chips vcore alone was good enough).

From the knowledgeable fornowagain back in July.
fornowagain said:
Semiconductor power P, P=kLV²F

Where:
L = Load (from software)
V = Core voltage
F = Chip frequency
k = Empirical constant for the chip.
Pd = Total cpu power
TDP = Thermal Design Power (stock power)

Therefore delta P, i.e. change in power. The constants cancel, rearranged for total power.

Pd = TDP x (F2/F1) x (V2/V1)²

Or a little easier to understand

OCed Watts = TDP x (OCed Mhz / Default Mhz) x (OCed Vcore / Default Vcore)²

online version

Its actually a little more complicated in real life as this approximation takes no account of the leakage, i.e. power used with no load, this also scales. But its delta is tiny compared to the dynamic values above, so good enough.
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Conclusion is that the thermal dissipation of the cooler at a certain temperature delta must be well over the TDP if you want to overclock while achieving this delta. In practise you normally want the largest surface area possible, which tends to mean the biggest heatsink you can afford. Watercooling can be looked at as a means of increasing the surface area well beyond the space available over the cpu socket.
 
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bigjimmyauk said:
now that would scare me i've been using XP for years ,never not once used vista
pondering what win 7 is like or wether to just stick with my good old XP pro
Click to expand...

On that build you'd be best on 64-bit Windows 7.

XP with a modern graphics card will only give you 3Gb of useable RAM however much you install. Don't ask why it's complicated.

95% of the time I use Mac OS, but Win 7 is a vast improvement on Vista.
 
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