i7-4700MQ (47 Watt) vs i7-4702MQ (37 Watt)

Wondering about what would be actually better to get out of these two processors the i7-4700MQ (47 Watt) or the i7-4702MQ (37 Watt)?

Taking into account the i7-4702MQ drops 200 MHz but is 10 Watt less than a i7-4700MQ should be pretty significant gain to battery life. Not only that should make for cooler running system.

Although when I look at notebookcheck in their review, the i7-4702MQ thermal throttles due to the low TDP where as the i7-4700MQ does not and can stretch its legs. Then again the i7-4700MQ is in a test/review laptop with some pretty beefy cooling. The majority of notebooks will have pretty standard cooling in most consumer units. Therefore the i7-4700MQ may thermal throttle in most notebooks out there under load.

http://www.notebookcheck.net/Review-Intel-Haswell-Processors.93189.0.html

 

From what we've seen from SNB and IB, the idle power (and heat output) is so close to call it the same from the highest quad cores, to the entry level dual cores (not the ULV's of course) when running idle/light/normal workloads.

Haswell will be the same within the Haswell lineup (and much better at idle than SNB and IB...).


Given the above, what is your intended usage (normal/light usage?... or heavy/intense?) - with either scenario if you'll be 'plugged in' for the heavy stuff, I would get the 4700MQ. Again; with either scenario, I would be getting a chassis that is built properly for a high performance quad core. This will ensure that with either processor you choose, you will be able to use it fully and with no artificial throttling.


So this means forget about the super sexy .5" (~12mm) notebooks - bigger in this case, is better (when performance, and hence, proper cooling matters).


And yes; that 200MHz does make a difference - 9% is a generational improvement (and you can have it now and enjoy it for the life of the system).


...

 

Yeah they are pretty much the same around idle, seems to be a limit where no more power can be saved, or minimal wattage at ~800 MHz.

I was expecting Haswell to have a much lower idle. Will be good if someone could post like a throttlestop screenshot (or the likes that shows power usage) of a Haswell mobile at idle.

I going to use it for gaming on the couch at nights, (also want it for the touchscreen, but that really has nothing to do with the load). Bit worried about a 47 Watt quad working with a 750M gaming. It will be this year Envy 15 which is really this just a 2013 dv6, therefore I am expecting the usual slightly ok cooling system that usually end up high temps and in and out of throttling.

Thinking about it I could use something like throttlestop to reduce the clock speed to that of a i7-4702MQ, thus use less power (which has worked with an earlier dv6 I had to stop it for over heatings). Though that will defect the purpose of having a faster CPU.

There is a small premium to pay for the i7-4700MQ over the i7-4702MQ, keeps me thinking there must be some value in it?

 

Wondering the same thing .

 

Faster clock speeds, it's also possible the 4702MQ might be missing features like V-Pro and VT-x or have a different IGP, you could look up the spec sheets on ark.intel. Intel has also been know to charge quite a bit for a small bump in clock speeds.

 

they are the same cpus, the 4700 is the 3600 OEM cpus

 

It's kind of like the Ivy Bridge i7-3610QM vs i7-3612QM, except the 3612QM demanded a significant premium over the 3610QM because it was a 35W quad core as opposed to a 45W.

 

In a highend notebook you can just lower the TDP to 37W anyway lol.

 

According to notebookcheck review about Haswell cpus, the 4702HQ seems to actually really consume less than 47 watts parts. It seems to be more significant than on 3612qm. I'd go for a 4702HQ and deactivate turbo boost to get more or less a 27W TDP. But that's just me, i hate noise and heat.

 

How easy is it to switch between throttling down when I'm just surfing and throttling back up when I need speed ? Throttling down will see a significant increase in battery life right ?

 

To see a significant increase in battery life, you would need to keep the cpu mostly idle (time-wise) - throttling down will do the opposite - it will keep the cpu awake for a longer time period to do the same amount of work it could have done at a higher (momentary, non-throttled) power level. This may or may not decrease battery life - but it will certainly not extend it appreciably (assuming any 'real' work is getting done, of course).

For example; if you're normally surfing with one/two tabs and maybe Word open... you might see a little better battery life.

If, you have a dozen or more tabs open, Word, Excel, a music player and maybe an instant chat client (or two) going - the only difference you'll see is possibly worse battery life - but almost surely worse system responsiveness, noisier (fans) and hotter (cpu is 'on' all the time...).

Depends on your 'light' usage scenario - but as in most things in this world - if you force things beyond their normal operating zone, they won't operate as efficiently (overall) as when you do.


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so what is the advantage 4700mq over 4702

 

It's simply built in tdp limits the 4700mq will turbo higher for longer (mostly likely just max all the time since 3.2ghz is a low clock target for 47w)

 

I don't think that it will increase battery life. It would be more or less the same. It's more for comfort. I don't like turbo boost because it kicks in when u surf as soon there are demanding animations on web content. It makes the temps rise quicky and force the fan to kick in for nothing sometimes. I had a core i7 2720qm and the lap was quieter when doing basic stuff with turbo boost off. And frankly running it at 2,2 ghz don't bottleneck at 1080p gaming. At 720p yes, but it concerns mostly what i call "the useless frames", basically any frame over 60 fps. And the fan runs at a more regular speed without turbo boost, it is less erratic without turbo ghz jump. But i guess it really depends on the lap and cooling system.

One thing is sure, most laps can't handle 45W quads right, they are always on the edge cooling wise. There are noisy ones that do the job right and and the quiet ones that throttle and heat. And Asus in the middle that is quiet and cool

From my point of view, i'd always go for the lowest heat output as soon as perfs are satisfying enough.

As for throttling, you can do that with throttle stop, or deactivate turbo boost via the bios settings or by putting 99% at max cpu usage in Windows power settings.

 

It is very easy to restrict the CPU's power by customising your power options (ie, "high performance" "balanced" or "power saver" when you click your battery icon) so even with a 4700mq you can achieve good power efficiency, when set to power saver, I have user set the CPU to 25% so it typically doesn't clock past 800mhz...... and it is still very responsive and fast, it is not at all noticeable. You can check and monitor your CPU frequency with HWinfo or view a live graph via OCCT - by default mine runs at 3.2Ghz constantly - it's very impressive.

You can also explore the amazing "ThrottleStop" which has user profiles, so you can define "power saving" and "gaming mode" if you want to directly adjust the clock speeds or limit them.

The lower TDP chips are typically much more expensive and are more made for laptops that cannot handle a 47w chip.

The TDP is more related to THERMAL management than battery usage.

therefore consider that with it being clocked slower, it will take longer to complete a task, thus using near equal battery capacity, so it's not as simple as a 37w chip uses 10w less than a 47w chip. Also those figures are the maximums, typically the 4700mq (and the 4800mq) use 38w and the 4702mq uses 30w so it only consumes 8w less, but as it's a slower processor it will be using it's 30w for a longer period of time for any one given task. When not in use, the cores use virtually no power at all.

 

I've now got my 4700MQ running minimum 3.4Ghz turbo constant by increasing all the turbo multipliers by 2 (even during stress testing on all 4 cores)

Running at stock voltage this pushed my total cpu package power up to 52w under synthetic load, and given that +2 on the multipliers seems to be the max I can select I thought I'd see how low I could get the voltage....

So I'm now running a -90.8mv core voltage offset which brings my total CPU package down to nearly 43w and there is no sign of any funny business yet, so I suspect it will go lower but I have noticed a significant drop in temperatures and fan speed (it doesn't actually step in to its higher more noisy fan profile now, the "just above" idle speed is almost enough

This makes me wonder, since you can so easily also reduce the multiplier, (by 24 so more than enough to replicate the 4702) and you can reduce the TDP and/or offset the voltage, I wonder do you really need the 4702 or could you set up 2 profiles in XTU to switch between "under voltage ultra cool 4702 mode" and "4700, under volt + OC" settings....

here's an idea of what I'm playing with so you can see your options..... if your bios supports it, officially or unofficially.....

 

Undervolting is back ?

Then of course in this case no need for a 37W cpu. Better get a 47W and tweak it.

 

I'm reading what your saying but I only understand it some of it .

Can you explain it to me like I have no idea what your saying ?

Are you basically saying that in a stock? program I can clock? the cpu down to use less energy / less temp and increase the clocks when I need to do work easily ?

 

Yeahs that's pretty much it....

To update previous progress.... I've notice that Prime95 stress test seems much harder than the XTU test's and at -90mv it reduced the turbo from 3.4Ghz to 3.3Ghz so I continued..... down to minus 130mv..... at which point Prime95 was running 8 threads and the CPU was holding 3.4Ghz constantly, but I did experience some instability, so I'm fine tuning in the -120 to -130 area to try and keep that 3.4Ghz permanently :thumbsup: - Although I think it probably will hold 3.4 during game play, as it is do doubt less intensive!

I'll point you here for further the latest on my 4700, as I can't keep flicking between threads - my brain TDP is very limited

http://forum.notebookreview.com/sager-clevo/720728-p150sm-gtx-780m-unboxing-photos-build-10.html - flick to page 10

 

thats interesting. I didnt know they 'kind of' unlocked the multiplier settings for the 4700MQ. I wonder if most manufacturers are supporting this.

 

I too am wondering if you can under volt the processor?

If that is the case being able to under volt, then the TDP can be lowered via software, therefore there is little reason to go for the i7-4702MQ, although if someone cannot run the Intel XTU software due to their laptop manufacturer, still may need the i7-4702MQ?

Most cases the XTU does not work with the average laptop. What laptop are you using to use the Intel XTU software?

 

Not him, but XTU is partially working on my Clevo W650SR with a locked bios. I can't adjust TDP, but I can adjust max turbo and voltages. I think Haswell having FIVRs might let XTU touch voltages.

So far, I am undervolted by 110mV, which increases turbo speed at full load and is about 10C cooler at idle.

 

Any updates on this? Is there a side by side comparison of two similar laptops using the 4700 and 4702? I don't mind sacrificing a little bit of performance for better battery life, but from what ive read so far, there might not be any really improvement in battery life at all.

 

Ivy Bridge was the same way i7-3700 and i7-3800 series CPU's were unlocked for +400MHz overclock. With Haswell i7-4600 is +200, i7-4700 is +400, i7-4800 is +600MHz overclocked.

 

The desktop chips are actually totally locked this time round so we are lucky intel are letting the mobile ones do it this time.

 

Soo you can undervolt / do some software magic to make the 4700 use the same battery amount as the 4702 ?

 

Yes if the motherboard supports XTU.

On the other hand the only way the 4700 would consume more battery than 4702 is if it was stressed significantly while on battery, but usually on battery users are just doing basic tasks like note taking, web browsing, basic desktop stuff so battery life would end up being very similar anyhow.

 

What about heat though? What would you need to adjust in XTU to have the 4700 run at that same TDP (35w) as the 4702?

 

TDP is not a static indicator - it is the most that the cooling system should be able to handle.

In low load usage case that HTWingNut specifies; the heat producing aspects will already be very similar.

Only at their maximum performance levels will the 4700 produce significantly higher temperatures - and again; that should be effectively mitigated by an appropriate cooling system anyhow.


Don't want to answer for HTWingNut - just trying to explain it from a different angle for you.

 

"Appropriate" for a cooling system is a really (really!) relative term. Remember, with very few exceptions better heat management translates directly to higher weight, and this is a very competitive market for "light" systems. Manufacturers are happy to make that tradeoff so that management is good enough to handle the 80% case, but if you try to push it to 100% you can get yourself in trouble.

 

I have i7 4702MQ..I can undervolt it in Intel xtu...Can undervolting cause damage?how much you suggest to undervolt to maintain system stable?70mv?is that too much?

 

Undervolt until your system is unstable or crashes or BSOD. Then add 10mV, so if it's unstable at 80mV, then run again at 70mV and stress it and see what happens, keep going until the system remains steady under stress. Then I usually add another 5 or 10mV on to that just as a safety factor.

Be sure to run your apps too that you will use most, because that's the configuration that you want stable, not just some benchmark. I've had systems that crashed with intense CPU stress tests like Prime95 but every other app ran perfectly fine, and the contrary where a high stress app worked fine, but an app crashed that didn't even stress the system too much.