Will the Alienware 18 lag on battery?

[comprocks]

I am planning to buy an Alienware 18 Laptop with specifications as follows:
Windows 8.1 Pro 64 Bit
Intel Core i7 4910MQ Overclocked
NVIDIA GTX 880M SLI (16GB memory)
(Website: http/www.dell.com/us/p/alienware-18/pd?oc=dkcwx03s&model_id=alienware-18#overrides=dkcwx03s:11~81PN6E)

When I checked out the Lenovo y510p with 4GB of total graphics memory, I was shocked to find out that it lagged on battery power and was only able to deliver full performance while connected.
The clock speed of the graphics cards used to drop from 2000MHz to 400MHz when the charger was removed.

My question is: Will the Alienware also experience something like this?
The total power consumption of the NVIDIA GTX 880M SLI is around 200W and the laptop has an 86W Hr battery. Will the laptop lag while gaming on battery power or will I experience no such issue?

Please help me find the answer because I do not want to invest so much money and end up with a laptop that lags on battery.

 

[sora]

I doubt it would lag on battery power if you changed the settings around in Control Panel > Power Management.

 

[comprocks]

I doubt it would lag on battery power if you changed the settings around in Control Panel > Power Management.

That was fast! Are you 100% sure though?
And what do you mean by changing the settings in Power Management? Are you saying that the power plan should be changed to High Performance or something like that?

 

[Shneiky]

Yes, your power plan should be performance. A laptop changes from Power saving to Performance when you plug it in. (unless specified otherwise).

If you use the performance mode - it will not lag. But you will have enough juice to run for 20-30 mins while on battery.

 

[caqde]

Most notebooks switch from the High Performance GPU's to the onboard IGP when going to battery due to the massive power consumption that those GPU's require the more powerful the GPU the less time you will have on battery. If you want decent performance on battery without sacrificing battery life and performance you would need to use a notebook with a lower end GPU and a decent sized battery something like a single Nvidia 870M.

You could also set your Lenovo to use the dedicated GPU on battery just remember you will lose a lot of battery life when using the dGPU compared to the IGP.

 

[comprocks]

You could also set your Lenovo to use the dedicated GPU on battery just remember you will lose a lot of battery life when using the dGPU compared to the IGP.

How do I do this? And if you are saying that the Alienware will switch to the integrated graphics (Intel HD Graphics 4600) on battery, how do I make it use the discrete/dedicated GPUs on battery?

Battery Life is not an issue, I am just worried about the lag (if any)

By the way, I read on the Internet that the lag on the Lenovo is because of an insufficient battery capacity (72W Hr)and the graphics (2x GT 755M) consume around 100W. I also tried changing the power plan to high performance. It does not help.