TDP Difference

Ok, so i was looking on Newegg and i saw the ASUS G50vt-X6 and X3 variant.

Now the X6 is selling for 1300USD w/ P8700, 2.53GHz, 3mb cache and super multi drive.

Now the X3 is selling for 1350USD w/ T9400, 2.53GHz, 6mb cache and blu-ray drive. Im not sure about the X3 waranty but the question i want to know for th G50vt series is...

What battery life decrease will i see from getting a 35watt TDP vs a 25watt TDP? The G50vt average life is around 2hrs and already that is freaking out, but for 50usd more i can get a better machine (not sure about warranty though) so I'm wondering how much will it negatively impact the battery life.

 

I don't really know the difference, but I can say the difference will be bigger under high load.

If you're going to use your laptop on battery with low CPU load, the difference will be small. My guess: 10 minutes.

 

On a battery life of 2 hours, 10 minutes sounds reasonable. But that is irrelevant compared to what you're actually doing, because at low usage, the CPU downclocks anyway. At a higher usage, the CPUs will use more power and produce more heat - but by how much depends on what you're doing.

 

The quoted TDP on both processors only applies at full load. At idle, the T9400 will still consume more power, but it should not be that much. If you're always running your machine at full blast on battery, you may notice a significant drop in battery life. Otherwise, the difference will probably be small. Ten, fifteen minutes on a two hour batter?

 

The difference in idle power is around 1W at most. Compared with total system idle load, let's say it's around 30W w/ 60WHr battery, the difference would be <2% or <5 minutes (while my numbers for the battery is an estimate to show a point, the approximate difference in battery would still be minimal). It only makes sense to use P processors on notebooks w/ low idle load such as those with integrated graphics and small screens, which can consume around 10-20W. Then a 1W difference is 5-10% as opposed to 1-2%.

 

okay thanks for your information. Great stuff, didnt know that on idle it consumes that much less power. Now to another question, say im playing games such as TF2 or L4D. Does this draw out maximum power for cpu that would result in much less battery life? Also, say that i got a 35w TDP rated CPU, what are the ways to make it reduce its power consumption. Im interested since ive never owned a laptop so i dont really know how to decrease power consumption.

 

Yes those games will create a high load for the whole laptop and will decrease battery life fast. For those games it would be good to have a P type CPU.

But if you want to game on battery, Asus is probably not the best choice because in general Asus does not do very good in battery life.

One way to reduce power consumption is to undervolt the CPU. I'm not sure how effective it is on the newer CPUs. Results can also be different for each individual CPU.

 

I've found out the battery pack is 6-cell, 11.1V, 4800mAH. That puts WHr rating at 53.28WHr.

Well anyways. I've looked up the datasheet for the P8700 and T9400 CPU. It looks like the 25W, smaller form factor P series Core 2 Duo mobiles are really lower power than the 35W T series Core 2 Duo mobiles. At all power points(full power, LFM mode, Sleep, Deeper Sleep, etc) the P series have lower current usage and TDP than the T series chip.

The effect is 20-30 mins at idle, light usage, or heavy.

(Remember, P and T is different bin. It's like comparing Standard Voltage with LV or ULV parts. It's not like comparing comparing Pentium M at 21W and Core 2 at 35W because the two CPUs have different power management and features.)

 

okay so undervolting is one way. Is there any other ways, specifically i mean ways like powermizer works were cpu uses very little power when it needs, or is that process automatic?

thanks for the responses btw. Also, what do you guys think that the 9-cell asus battery can reach as it cost 170usd from gentech and wondering how effective it would be?

 

any help appreciated for my above topic is welcome...

 

Its done automatially, almost all mobile cpu's these days include power saving features.