Any reason for different battery life between XPS2 and 9300 ??

6800 Ultra consumes around 66.1 WHr of power.
6800 (non ultra) consumes around 26.7 WHr.

It would be nice if you could clock it down.
But considering the huge difference if you can clock both down I would say the non-ultra will still consume less power.

No-one to my knowledge knows for sure but I think there is more to the ultra than just overclocking the memory.

Edit for accurcy of number i was off by 4 on the Ultra
and the following is from Toms Hardware.
"While a Go 6200 has a maximum power consumption of 8.7 watts (including memory), the Go 6600 18 watts and the Go 6800 26.7 watts, the Ultra chip swallows a record 66.1 watts"

The various versions of the go6800 all have power management which automagically underclocks, so you don't have to manually underclock.

There are several factors that could affect GPU power consumption:

core and memory clock frequency
type of vram used
termination (needed for higher clock rates)
number of transistors in the core
die size
die semiconductor material
voltage
etc....

If you're a gamer, you're probably willing to sacrifice battery life to get the fastest mobile GPU around. Why would you even be talking about underclocking? If you're not a gamer, why would you want an XPS2?

I think we're still waiting for definitive answers to all of those questions. We've definitely had rumors that the VRAM is different, the die sizes and process are different, the clocks are different, and the cooling solutions are different. IOW, there is strong evidence that they are different

If you really need longer battery life, i would just pick up another battery. Even if you downclock the GPU, how much more time do you really think you'll get from it? And like Dellbert already said, modern day GPUs do have built in clock regulators that increase/decrease depending on your usage.

That's crazy...the 6800 go ultra sucks down way too much power for being an overclocked 6800 non-ultra. I know the ultra has GDDR3, but that has a lower voltage than DDR1 and 2. Despite the memory, I can't think of any hardware differences. I do want good battery life, so we'll see how the ultra responds to under-clocking. I'm going to try coolbits when I get my XPS 2.

For the most part, my XPS 2 won't be moving very far. I can assure you that I will get $2900 worth of gaming out of the machine, but I want to explore this issue. I do a lot of work on my computer too, so good battery life is something worth putting a little work into. It's not like it's difficult or time consuming to enable coolbits and underclock the GPU. But whatever, if 2 hours of battery life is what I get, it's what I get.

I need the longer battery life when I'm on a plane and want to watch a DVD. It would be nice to get enough battery for at least one DVD.

Thats something a spare battery is good for.

Still would be nice to watch a whole DVD on a single battery charge -- nothing's worse than getting to that intense action sequence only to have the laptop shut off due to a dead battery.

I'm definately not expecting anywhere near the 4-5 hours of battery life I get out of my AOpen 1557GLS barebones, but if I can get 2.5-3 hours of light use, I'll be happy.

(and yes, I ordered a spare battery).

Go first class where they have plugins J/k, I'm wondering the same thing actually and for the same reason.

could be because they compared the 6 cell 53WHr 9300(which is the base option) with the 9 cell 80WHr xps gen2.

Who are "they"?
If someone have compared the batterylife of the i9300 vs. the XPS gen2, then I would really like a link!

"they" = Dell

Which Notebook is Right for Me Comparison Chart
In that chart it shows the XPS2 as having better battery than 9200.
But thats becausee the XPS2 comes default with 80Whr and the i9200 comes default with 53WHr.

That also explains why the XPS2 weighs just over a half pound more than the i9200.

Ok, I'm bored, so let’s take a look at some numbers...

The Go6800 has a TDP of 26.7 watts, while the Go6800 Ultra has a TDP of 66.1 watts.

Now, a XPS Gen2 has a battery life of 133 minutes = 2,22 hours, according to PC Magazine, and a i9300 with a 80Whr battery has a battery life of 5.2 hours, according to Dell (note the test conditions at the bottom of the page).

That means, that the XPS Gen2 consumes 80Whr / 2,22hours = 36,04 watts, while the i9300 consumes 80Whr / 5.2 hours = 15,38 watts.
Note: The XPS Gen2 tested by PC Magazine had a faster CPU.

Assuming a x300 was used when Dell measured the battery life of the i9300, and that it consumes 2 watts in idle mode (This is nothing more than a guess, but according to ExtremeTech a Radeon 9700 consumes 2 watts during DVD playback), then the rest of the i9300 and XPS Gen2 consumes around 13,38 watts.

If this assumption is correct, the Go6800 Ultra has a idle power consumption of 36,04 - 13,38 = 22,66 watts.

If we assume that the ration of the TDP for the two cards is the same as the ration of the power consumption in idle mode, then a idle Go6800 will consume (22,66 / 66,1) * 26,7 = 9,15 watts.

This leads to the conclusion, that a i9300 with a Go6800 will consume around 13,38 + 9,15 = 22,53 watts, and have a battery life of 80Whr / 22,23 = 3,55 hours

The big question is:
How much power will a x300 and Go6800 actually consume when idle, and how many errors do I have in this calculation?

Ouch...

Small business charges you tax and shipping so it kinda evens out with Home price

yeah that seems to be correct. but seriously if you want great battery and ok gaming go for the 9200 with the radeon 9700, or the Go6800, but really how much difference is there between the ultra and the normal 1. 2 or 3 frames per second?

Did you read the footnote? The 5.2 hours is for a 9200, not a 9300.