i5 vs i7? Is it worth it?

I'm looking at a new MacBook Pro 15". What's the major differences between the i5 and i7? Or, should I save the $$$ and go with a not so new model (Core 2 Duo)?

 

Only you can answer this question. What are you planning to do with it? Video editing, photoshop, checking emails?

 

I'm replacing my Alienware M17x (size and weight), as I'm traveling more for work and MBA program. Occasional gaming, but more work related stuff, and videos for the plane ride.

 

I love the i5, but the i7 is even better and uses the same amount of battery. The gap from the i5 2.4Ghz to the i7 2.66Ghz is ~$400 more. The i5 should be great for you, depending on the games you play.

 

Nothing in that list would benefit from an upgrade to the i7, at least that you would see without benchmarks. Games are all still (mostly) gpu limited, and the rest won't even come close to stressing even the i5.

 

There's not alot of time devoted to games (flight sims). It mostly goes to school work and PPT. I hear there have been heating issues with the i7. Would I be paying more $ for my troubles?

 

Keep the money and get the i5. No reason for you to upgrade to the i7 at all, unless you decide that you must have it .

 

So, the 2.53GHz, i5, 3MB should do alright for DVD and most applications (iTunes, Excel, PPT etc)?

What about the graphics? Is it worth it to go from 256 MB to 512MB? I'm trying to justify the price increase between the three 15" models available.

 

1. Yes, plenty (overkill for those, actually).

2. No.

 

Cool, Thanks for the quick replies and assistance. Now, if only Apple would offer a trade-in program for PC's.

 

incorrect. under load, the i7 uses considerably more power.

 

You know... I don't see why people still need to ask if those CPU can runs those applications nowadays or even all the applications out there in the world.....

My Centrino 2.26Ghz Single Core can run iTune and Excelt and PPT... of course...

lol

Much more my 10 years old desktop single core or my 8 years old 700Mhz laptop still able to run today common Applications like iTune. Just slower. (not talking about games or 3D)

 

I ordered one with i5 plus SSD instead of going for the i7.

Seriously, where did you get this info from? Because the Intel datasheets say they consume the same. Get the facts.

 

The Intel datasheets only state TDP, which doesn't really tell you much, especially because the same TDP tends to be applied to entire classes of CPUs in broad strokes.

The fact of the matter is that the power consumption of a CPU increases with clock frequency, so the i7-620M will inevitably be more power-hungry under load than the i5s - but probably only slightly. I've seen varying results from actual testing, however - compare this and this.

 

Yeah I know that notebookcheck article, it has been very "debated" in other sections of this forum, to say the least.

But have you actually read the datasheets? There are several places where they cleary state that TDP is power consumption, or use TDP as a measure of power consumption, under worse case load.

 

Yeah, I think the second article is probably much closer to the truth.

I have indeed read the datasheets, and Intel defines TDP as maximum power consumption in "realistic" worst-case scenarios, without a clear definition of what exactly "realistic" means in this context.

TDP is handy as a quick reference value, but it still doesn't tell you how much power the processor will consume at idle, or under varying levels of load. TDP figures also tend to be approximate, and applied to entire classes of CPUs, as I said before - Intel rates the i3-330M and the i7-620M as having the same TDP, yet it is almost certain that the i3 is not as power-hungry as the i7.

 

Sorry dude but you are going against logic.

If the clock is higher the power consumption will be higher, it's physics.

 

Exactly. More cache + higher clock = more power consumed. TDP doesn't tell you anything about power consumption as it is the maximum power needed to be dissipated by the heatsink.

 

Essentially all of the power consumed by a CPU becomes heat, though.

 

True, but the TDP value doesn't show this. It only has the maximum heat output. Power consumption is a dynamic value and can fluctuate quite a bit depending on the demand given to the CPU.

 

Yeah, I said something to that effect earlier.
Also, strictly speaking, the CPU can exceed the TDP value because Intel only defines it as during "realistic worst case applications", though. From the Arrandale datasheet:

 

centrino is not a processor, it's a intel standard for having intel wifi, intel chipset and intel processor

 

Well, I have to agree that it's logical for higher clocks to consume more... but power consumption depends on other things as well.
Anyway, what ticked me was the mention by ajreynol that the i7 consumes "considerably more power" (talking about battery life)... 10% difference in processor speed / power consumption (which I'm still skeptical about until there's a 1:1 comparison with all else being equal) does not equal 10% difference in battery life.

What you quoted mentions that the TDP of each component can exceed the component's designed TDP, it's the local maxima vs global maxima: when a component is at it's worse case other components can be at 10%, it's not necessarily the worse case for the whole system.

 

The term "local maximum" doesn't really mean what you want it to there. Also, my quote from the Intel datasheet was not directed at you, but at the statement that the TDP was maximum heat output, which isn't exactly true.

I understand your main point, though - because of other components, a 10% increase in power consumption in the CPU is going to mean a much smaller percentage in the overall system power consumption.

 

Of course but here we are talking about same architecture, same manufacturing process, etc.

Just take a look at anandtech's update on i5 vs i7 battery life on the new mbp 15", i would say that it's testing is pretty realistic.

 

If you're talking about this update Apple's 15-inch 2010 MacBook Pro: More Battery Life Tests, High Res Display Evaluated - AnandTech :: Your Source for Hardware Analysis and News it seems to me they are comparing the battery life of an i5 with the standard screen (the test results they had before) vs. an i7 with the hi-res screen...
So yeah, their tests may be great, but they "forgot" to mention the screen difference in that page. Not that all the difference in battery life is caused by the screen, but some of it must be.

PS: all this might seem like I'm trying to defend "my" i7... but I actually ordered an i5

 

Yeah some of it, 1% to be more precise .

PS: I'm defending the i5 but probably going to i7

 

I wanted to mention the era of centrino. Around those times, Pentium M.