Battery Life: i5-520m vs i7-620m

Does anyone know how much more battery life (rough estimate) you'll get with an i5-520m compared to an i7-620m?

I'm looking at an HP ProBook 4420s w/Intel integrated graphics, X25-M SSD, no OD bay.

I'm looking at getting the 620m because cost isn't a factor atm, but battery life IS. If it's just going to be 20 mins give or take of extra battery life, I'll take the 620m. But if it's an hour or something, I'll take the 520m.

Let me know what you think.

 

Ya its not going to be anything substantial, I know on my old laptop, going from a t5850 to an X7800, with twice the TDP got very similar battery life. The Intel graphics and the SSD will also help increase battery times.

 

I can pretty much guarantee the difference in battery life won't be an hour for a ProBook. If we were talking about netbook levels of battery life (at which point we wouldn't be talking about high level i-cores, but I digress), then the change in processor might be as much as an hour, but at the level of battery life that a ProBook has, I wouldn't expect a difference of more than 15-20 minutes.

 

They use the same wattage. Unless you are really stressing the CPU to the point where the i7 is clocking itself to max capacity the battery life difference will be negligible (maybe 10-15 minutes at worst.)

I would get the i7 for the performance gain. Odds are you won't be doing anything too stressful if you are trying to maximize battery anyways and when plugged in performance will decimate the i5.

 

They are the same chip, just one is clocked a little higher than the other. With all the modern power saving features intel has built into their chips, the only time you will have different battery life between the two is when you are putting high loads on the processor.

They don't use the same wattage. That is not what TDP is.

 

The power consumption difference is pretty small but will be noticeable more on smaller screens. It also depends if you are idling/doing light tasks or stressing your CPU on battery.

 

Thanks for the insightful replies guys. I mostly won't be stressing it when on battery. Also, I believe this notebook throttles the CPU on battery, so it won't even be able to use 100% without power.

Do you think I might manage 7-8 hours battery life with the 9cell and 620m?

 

I can say that i7-620m will pull more power under load then i5-520m for sure.. but if ur not doing strenous stuff on battery , going from i5-520m to i7-620m should be at most 15-30 mins of loss of battery.. if using under load , then it might cause more battery loss.. and as for battery life , i don't think 7-8 hours will be realistic... more like 5-6 hours with 9 cell.. u might want to get a 12 cell..

 

I'd love to go with the largest battery avail., but as far as I know, the 9-cell is the largest for this model (4420s). I might just have to get two.

One more question, I went with the integrated graphics just for battery life, but if I have to get two 9-cells anyway, how much less battery life do you think an NVIDIA NVS 3100 would get?

I really wish some good 14"-15" core i5 ULV processor laptops were out.

 

The NVS 3100M is a derivative of the 310m, which I believe may be an integrated chip. It is four times as powerful though, and though you may get more battery life, as long as your not doing a lot of number crunching (ie CAD, ArcGIS, etc) on the battery, you wont notice a difference; maybe 10-15 minutes.

 

get the NVS3100M if u have the choice.. it won't use much more power than intel GMA HD and the extra power might help later on... as for battery , Hp usually has a seperate 12 cell which u can buy from their online store but not on ur laptop configuration.. that was the case for Dv5t but don't know about urs.

 

Ok. I can't find a 12 cell anywhere for this model. But, I'll look into the 8440p (w/NVS3100M) as it has a 12 cell.

 

am I right in saying the difference in power between these 2 CPUs is nominal (< 10%), such that it would make more sense to spend the money it costs to go from i5-520m to i7-620m instead on buying a good Intel SSD?

thanks in advance for the insight.

just seems that based on what I'm reading, with the i7-620m you're giving up more battery juice (620m appears to eat ~15W more energy under load) for less than a 10% increase in power.

or am I misunderstanding what I'm seeing?

http://www.notebookcheck.net/Review-Intel-Core-i3-i5-i7-Processors-Arrandale.25085.0.html

 

Counting Turbo Boost, the i7-620M is clocked 15% faster on two cores, and ~14% faster on one than the i5-520M, and it has 4MB of L3 cache rather than 3MB. You're completely right that spending the money on an SSD would be a better idea for most people.

 

understood.

I'll start looking around at my SSD options, then.

 

I have to ask: what do you do on a notebook? For the majority of people there will not be a tangible difference in performance between a Core i3/i5 and a Core 2 Duo. You could just get a current C2D-based ULV notebook and be happy now.

 

If you can find it, 540 seems to be the best option.

 

"Best" depends on the criteria you're using, but the i5-540M probably offers the best performance per watt.