underclock my x1800?

hey all,

i got an alienware m5550, which u probably know is not a cool laptop, ive undervolted the cpu to 1v and it is stable as hell and reduces temps by about 10-15c.

i was wondering thou, to keep things cooler still, is it worth underclocking the gpu (x1800)? i dont mind a slight performance hit, so long as it helps cool it by a few degrees.

i already have a notebook cooler, but during winter, room temperature gets high with the heating being on, and the cooler has minimal effect.

any thoughts? i found that the clocks for the x1800 should be 450 and 500, but mine is currently 400 and 450.

 

It'll help a bit - whether it will be enough to be noticeable I don't know. The thing is, it won't help as much as overvolting, for the same percentage reduction. That's because there's a linear relation between clock speed and power usage/heat, versus quadratic for voltage (not accounting for leakage within the part here or elsewhere). So if you reduce the clock by 20%, you'll save 20% power/heat (ideally - leakage causes the savings to be less), whereas if you reduce voltage by 20%, you'll save 36% power/heat (again ideally). But yes, it could certainly help.

What are your temps, btw?

 

thanks for the reply,

when idle its around 47-53, when watching tv/films around 57-61, when gaming on cod4 for long hours around 67-73 (this is with the undervolting, it was well over 80 before) it has peaked on 75 when i have the heating on for a cold day... when its like this i take the bottom off the laptop and have it directly on top of the cooler, helps no end, but not an ideal solution.

trouble with the x1800, there is no heat sensor, so i dont know the gpu temp, just cpu.

its cool as ice depending on the room temperature (which is suppose is obvious), and heading into winter i wanna get some kind of solution ready, as i just bought all new parts lol

what clock settings would u recommend for the x1800 for a fair performance/temperature ratio?

p.s. the x1800 with an undervolted cpu runs a HELL OF A LOT cooler than my x1400 ever did - im quite surprised how good undervolting is.

 

any thoughts?

 

Unclocking the GPU doesn't do much since voltages are still the same. GPUs automatically down clock already.

 

so would setting the clocks to 450 and 500 instead of 400 and 450 cause more heat or the same? i always assumed more, so i would of thought it would work the other way, downclock = less heat. what you say makes sense (im quite novice to gpu's so please forgive my ignorance )

 

The heat shouldn't rise much if at all (if it rises, it will be negligible like 1-2 deg C at most), since power is calculated by voltage times current and heat is just the energy that is lost due to inefficiencies in converting power into useful work (physics 101).

 

learn something new everyday ^^ thx

 

They do downclock automatically - but only on 2D mode or if they're overheating. If you put the 3D clocks lower, you'll have lower speeds and temperatures while gaming. If you put the low-power 3D clocks lower, you'll have lower speeds/temps while it's running slow to avoid overheating. If you put the 2D clocks lower, you'll have lower speeds/temps at idle. You can of course do all three (in RivaTuner at least - don't know what all other tools support this).

Voltage times current, yes - and the current is dependant on part on the clock speed. So lowering the clock speed will lower power usage and temperature. Not by a ton (unless you really underclock it - part of why there's a difference between 2D and 3D temps), but a bit.

Those temps don't sound too worrying, so long as your model isn't known for high GPU temps relative to CPU temps. 75 is a perfectly safe CPU temp, and GPU temp, and in most notebooks GPU temps are similar to CPU temps (obviously it does vary though).