i7-740qm vs i7-640m Battery Life

Hello Guys,

I am debating between
i7-740QM, 16G Ram, FDH Screen, FX 1800M.
Funny HP says 5hours 30min battery life

OR

i7-640M, 16G Ram, FDH Screen, FX 1800M.

My main concern is battery life. I am reading that the i7-Quads do not have an onboard video so it will always be using the power hungry FX1800 and I travel alot.

anyone have either othese laptops can tell me battery life?

 

i7-740QM is a Clarksdale cpu built using 45nm tech. It's rated at max 45W TDP.
i7-640M is a Arrandale cpu built using 32nm tech. It's rated at max 35W TDP. It also has an IGP onboard.

The i7-640M should therefore consume less power. Moreso if the system has switchable graphics so can use it's IGP.

If you want a Quad core AND an IGP or switchable graphics then look at Sandy Bridge notebooks.

Consider too a DIY ViDock to add graphics capabilities to systems without such an option. Can be made portable enough to carry around.

 

The 8540w owners thread has a datapoint. Several different battery configurations are possible (Primary: long-life[3yr, many cycles] 68Wh, standard[1yr, faster charge?] 73Wh. Optional attached external: extended (+52Wh), ultra (+95Wh)). This datapoint is with the 68Wh long-life:

The 8740w Benchmark thread has some data which may be useful:

1. The 620M comes with a dual-core motherboard, which only has two dimm slots. 16GB RAM is currently significantly more expensive for a two-dimm motherboard (need two 8GB DDR3 dimms) than the quad-core motherboard.
Siorah has gotten an 620M to work in a quad-core motherboard with four dimm slots, though it only recognized 16GB RAM on a 32GB system.
Update on the 32GB
8740 AND 8540 Memory Configurator

2. Siorah has reported similar numbers for the 8740w (not 8540w), after swapping a 620M into a 720QM system.
The times should be low compared to a 8540w system because
- the 8740w has a larger screen
- the 8740w has a Quadro 2800M, not a Quadro 1800M.
- the 8740w with 620M was measured on a quad-core motherboard with 4 dimm slots, not 2.
But shows roughly how much difference it may make.

Code:

8740w battery times summary:

CPU Model:	720QM	620M
CPU TDP watts:	 45w	 35w

Idle minutes:	135min	157min (+22min)
MP3 minutes:	118min	134min (+16min)
DVD minutes:	 98min	111min (+13min)
BD minutes:	 83min	 92min (+ 9min)

Collected 8740w Owners Benchmarks Data: Battery Times

 

Also, I don't think the 8540w can use the IGP.

 

Thanks everyone!

I know the processor QuadCore uses 10Watts more but what concerns me more is the videocard power draw. If the Dualcore can disable the nvidia videocard which uses 45Watts on it's own.

So surfing the net the Dual core would use 10+45 = 55Watts Less than the Quad.

Is that true? if so the battery life difference should be significant.

 

Will you be using 3D while on battery? If not, consumption will be less. If you plan to mostly use battery to read email or text without video/animations, notice that the Quadro 1800M only uses 3.8w when idle (PowerMizer, EnergyStar).

The 1800M does not support Optimus.
NVIDIA Quadro Mobile Solutions
No Optimus means that in order to use both the 1800M and the IGP, the notebook manufacturer would have to provide a switch on the motherboard so that either the 1800M output or the IGP output could be wired to the internal screen.

I believe the 8540w only wires the 1800M to the screen, not the IGP.

(As I understand, for notebook+GPU combinations that support Optimus or equivalent graphics switching, the GPU result memory image is copied back to the IGP memory, and only the IGP output is wired to the screen. That additional copying also uses more power, so Optimus might be less efficient if you frequently use 3D while on battery.)

 

I didn't know that about the GPU.

HP EliteBook 8540w Mobile Workstation (ENERGY STAR) (XT970UA) specifications - HP Products and Services Products
I'm leaning towards this model now.

i7-740QM Processor (1.73 GHz, 6 MB L3 cache)
8 GB 1333 MHz DDR3 SDRAM (I'll add another 2 DIMMs of 8G for a total of 16G)
320 GB 7200 rpm SATA II
DVD+/-RW SuperMulti DL LightScribe
15.6" diagonal LED-backlit FHD anti-glare (1920 x 1080)
NVIDIA Quadro FX 1800M graphics with 1 GB dedicated GDDR5 video memory


I currently have a
i7-620M
Nvidia Quadro 880M
8G Ram
256GB 7200 RPM HD
DVD+/-RW SuperMulti DL LightScribe
15.6" diagonal LED-backlit FHD anti-glare (1920 x 1080)

and I about 2hours and 30minutes of battery life on it.

I'm hope to keep atleast 2+hours with the Quad core..

 

Anyone here with a Quadcore?
Can you please run Osiris Development - BatteryBar, the most accurate battery meter for Windows
it's a neat free app which tells you how much power your using.

With 1/2 screen on my 640m I get discharge rate of -17,438mw which gives me a little over 3hours

 

I will use that program

 

Anybody at home? I installed that Battery Bar however I do not see where I can find information about how much power I use.

 

Click the battery on the bottom left and it will tell you charge rate

 

Yep. I needed to turn AC off first
56-57 using furMark (gpu)
27-28 idle + browser
how can i stress CPU without prime95?

 

Unplug and leave on balanced. and do nothing. put it on 50% brightness and see how much usage it is using.
for me it is 19,000mw