Core i7 2620M -- why dual core i7???

I don't get the logic of making a dual core i7. Why not call it an i5?? There are no quad core i5's are there?? And most i7's are quads, right? So why does Intel make an i7 with a dual core?? Just to have a less than 45 watt range of cpu's?? Doesn't make sense to this amateur.

I'm scratching my increasingly hairless head over this one.

 

for the 2nd generation i7, it is a quad core is you see a QM at the end. Eg i7-2630QM.

 

For those who want a higher end dual core without buying an extreme chip. Remember:

i3 = budget
i5 = mainstream
i7 = enthusiast

Sure the i7 line is mostly synonymous with quad core chips, but is overall a segment for enthusiasts. Some of those dont have a need for quad core, but want a stronger chip then what the i5 series can offer.

 

i7 have higher out of the box clock speeds, slightly more cache and have a higher turbo frequency. But overall you are correct, dual core i7 have almost no advantage over the i5.

 

Except that I am looking at an i7 2620M -- which I believe is 2nd gen?? -- being offered on a W520, and it is a dual core. So it appears that not all 2nd gen i7's are quads. At least not the 2620M. It has Optimus, which I believe is also only in 2nd gen cpu's, but it's only a dual core.

Which comes back to my original question: if it is only a dual core why isn't it an i5??

 

Because as said before the i7 branding is not only reserved for quad cores, it is for those who want a top of the line Intel processor in performance, whether it be dual or quad core.

 

Yes, thank you, I have noticed that when an i7 has two letters (e.g. QM) following the 4 digits (e.g. 2630) it's a quad core, but if there is only one letter (e.g. i7 2620M), it's a dual core.

But that's what I don't get: if it's only a dual core than why not call it an i5?? Why an i7?? The i7 dual cores *do* have 4 MB of cache, whereas I believe all i5's have 3 MB only. So, is that the only difference between an i5 and a dual core i7: one MB of level 2 cache???

OK, marketing descriptors noted, but what exactly is giving a dual-core i7 that "top of the line" performance over an i5?? Is it only the extra one MB of level 2 cache on the i7 chip?? Or does the i7 dual core have other features that make it "top of the line" over the equally dual-cored i5??

Thank you, Sphinx. What makes the i7 dual core stronger than the i5, aside from one more MB of level 2 on-board cache?? Anything else??

 

Core i7's have the faster clock speeds, the most cache, and the highest Turbo boost speed's of the gpu and cpu. That is it.

 

The i_ distinction is pure marketing, with minor hardware differences that lead to minor performance differences. The i3 series lacks Turbo Boost, but really doesn't perform all that much worse than some i5 CPUs. The i7 dual core series has more L3 cache than the i5 series, but has negligible performance difference (while being significantly more expensive!).

A good idea when comparing processors is to compare pure specs and performance data, and ignore the naming scheme.

 

Yes but Core i5 will outperform Core i3 in single threaded applications with Turbo Boost prevailing. Sometimes the i7 dual cores aren't significantly more than the high end i5's and for some people 50 bucks doesn't make a significant difference.

 

Bingo! The naming of the I7 is mostly marketing. It sounds faster than the I5. It is, I believe, a carry over from the I5-I7 distinction in desktops.

Bronsky

 

Hm, I thought the i7 supported some instructions or hardware encryption that the others lacked. And perhaps it has superior hyperthreading - or was it the i3 that lacked hyperthreading? I forget...

 

The differences between an i7-2620M and an i5-540M are so insignificant, per Intel:

Compare Intel Products - i5-2540M (3M Cache, 2.60 GHz) and i7-2620M (4M Cache, 2.70 GHz)​

Just go down the list for entertainment value.

For dual-core, stick with i5 (with integrated GPU) and put the money on SSD and RAM. Heck, stick with i3 in most cases!

 

Slightly faster clocks and turbo boost speeds. Real world performance difference? Minimal. The only thing that will show a real difference (and minimal at that) is benchmarking. But honestly if I were going to spend the money on an i7 it would be for a quad core and not a dual core. If I was in the market for a dual core the i5 chips are close enough to not really warrant buying a dual core i7 IMHO.

 

usually people go for the i7 for several reasons:

benching (hey if you like it?)
future proofing (not that valid)
or in my case because I would need it, since its bundled with something I want. (terrible!)

aside that there is no reason to go for the i7 dual core

 

Have any of you compared HD encoding using the Intel Core i7-2620M, Intel Core i5-2540M, and Intel Core i7-2720QM ???

I'm looking for actual results not what-if paper analysis.

By the way, why was this thread moved? I am comparing the T520 to the W520 for a purchasing decision.

 

i3, i5, and i7 have nothing to do with core count or performance.

 

Ahem... Someone is OCD lol

 

They all have hyperthreading. Their instruction sets are not linked to the 3/5/7. Hyperthreading is the same for all of them.

The difference is with the pins and it has nothing to do with anything performance wise.

 

lol the i3 doesn't have turbo boost unlike the other two. I'd say its down to marketting but it would be better if they kept i7 for only quad cores and i3/i5 for dual cores with the 3 being the budget the range and 5 being the high end dual cores.

 

Pretty sure this is just to play to the ear of consumers. If they would just make the specs of their processors readily apparent like they used to, we wouldn't have all this crappy confusion.

The naming conventions they have now are completely arbitrary.

 

Hardly. The naming conventions are used to get you to buy the higher number. That isn't arbitrary.

 

the naming conventions including the numeric model #s are well defined as to what means what.

 

Intel I5 750 and 760 on the desktop are quad cores.

 

if arks.intel is mostly right,

i3 are 2/4 (C/T) with hyperthreading

i5 are 2/4 (C/T) with hyperthreading

i7 or i7 extreme is 2/4 or 4/8

desktops are a littler simpler, but still a mixture as well

 

The Core i-series naming hasn't made any sense since Arrandale/Clarkdale launched in 2010.

Sadly, for the average semi-computer literate customer, an explanation like that confuses more than it clarifies...

 

I agree, but this is what I mean by arbitrary:
subject to individual will or judgment without restriction; contingent solely upon one's discretion: an arbitrary decision.

 

According to the wiki page, dual-core i7 looks like it has more L3 cache than i5. 4mb vs. 3mb. Looks like that's the differentiator they used for marketing.

 

someone please benchmark same model laptop with identical specification except the CPU, with i5-2540M vs. i7-2620M.

 

To be honest I wasn't even thinking of going to an i7 of any kind until I found a nice deal for a new Thinkpad W520. I've been looking for a T520 with my specs (basically the 1080p screen) but they are rare. The W520 came up and it is very tempting, more than I need really but the price is less than $1600, 3 year warranty and free shipping included.

It comes with a dual core i7, the 2620M.

Basically I was just wondering why Intel would market an i7 that was *not* a quad core, but I guess from what I'm reading here and elsewhere that the added MB of on-die cache and some other features makes it a bit stronger than the best i5. I could be wrong, but that's what I see at the moment.

Yes, that makes sense to me. The dual core i7's seem out of place, imho. Market the high end dual cores as i5 "Performance" or something like that.

 

dual core i7s lets Intel use/sell more parts that failed initial inspection.

AMD does the same thing with their x2/3/4 CPUs.

 

I like the i7-620M/2620M. They do outperform i5's enough to justify there price in my opinion, because their turbo boost frequency is so much higher, AND they don't have the high TDP of the quad core i7's. Many people don't see the improvement in turbo boost, but thats because the algorithm that controls TB is very heat sensitive, in other words, if you notebook's cooling sucks, TB isn't going to overclock any cores.

Play an CPU heavy game like SC2 and you'll see, just like synthetic benchmarks, the 2620/620 outperforms the i5-540/2540 by a solid margin (10-15%).

No, this is wrong. You are right that AMD does take CPUs that dont pass QC from the higher end wafers, but intel does not. i7-620's are not revolted CPU's with cores disabled. Link me if you think I'm wrong.

 

No they don't. Intel makes separate 2 and 4 core parts.

 

Marketing marketing marketing. Plain and simple.

Although I still don't understand why they don't make all i7's quad, i5's turbo boost duals, and then i3 fixed clocks. That would clarify things a bit. No clue why they prefer to confuse customers than make it simple.

 

Which will run cooler (for video and music playback while simultaneously running Skype, Thunderbird, Google desktop, an Anti-Virus and a HIPS firewall, plus 35 tabs of Firefox in the back-ground .... go ahead and flame me!!! ):

the i7 2620M (dual core @2.7 GHz native) or the i7 2720QM quad core @2.2 GHz native) ??

 

I doubt there would be any difference. The quad could run hotter, but that is only because it is capable of doing a lot more processing.

 

Really? The 2620M is .1GHz faster than the 2540M and TB's .1GHz more. Then there is the 1mb more L3 cache. That is really worth paying more to you (in the case of the Lenovo X220 it is only worth it because you get a USB 3.0 port )?

 

The i7-2620M is overpriced crap plain and simple. Despite being a dual-core it's almost as expensive as a 2720qm. It's even more expensive than a 2630qm everywere I looked and will yield slightly better performances in a few situations when you don't even really need that extra-power, and will literally get crushed in all other scenarios that benefit from 4 cores / 8 threads. Want performance ? Go for a 2630 or 2720qm. Want a cool running CPU ? Save yourself 100 to 150 bucks (buy an SSD or other stuff) and go for i5-2520 / i5-2540M. You'll lose 2-5% performance, big deal.

 

Well, it's interesting because the 2620 dual is rated as 35 watts TDP while the 2720 quad is rated at 45 watts. The 26 runs at native 2.7 GHz while the 27 runs at 2.2 GHz. Now my T60p thinkpad has an old simple dual core that runs from about 450 MHz up to 1996 MHz with the older Speedstep. I wonder with the newer Speedstep whether these newer CPUs would tend to slow down as much with no/little load, and thus run cooler. Or would their inherent designs (with 35 and 45 TDP) have them running always at higher xHz??? and thus warmer??

The thing is that I'm looking at a couple of offerings on eBay which are pre-configured with these two i7 processors (2620 and 2720), and they are very tempting deals, both on W520 machines.

 

It all depends on the price offered for both systems and the laptop's cooling. The i7-2620M is by no means a bad CPU, it's simply weirdly overpriced imo.
Sandy Bridge quad-cores are great but they require a decent case to run at acceptable temperatures and make good use of turbo boost.

 

From what I'm reading, the thinkpads are doing a great job in the cooling department. Anybody hear otherwise??

Price I'm seeing is less than for $1600 for either the W520 with a 2620 or a 2720.

OOTM

 

Intel does this because consumers are stupid. They see core-i7 and go oooooo, must be very expensive. So they'll dish out the extra bucks for it. Plus its rated at 2.7Ghz base and 3.4Ghz turbo, which are big numbers to most folks, and they think that big numbers are better, hence they will buy it. Intel is smart, making people dish out extra dough

 

I'd go with the i7 2720qm.
It's got 4 cores, great for multi-threaded software, and it will downclock to a minimum in order to lessen the power drain when idle or not doing cpu intense tasks.

It also depends on the price differential and what you'll be doing with the computer in question (but I'd still opt for the 2720).

I agree that the i7 2620m is absurdly overpriced next to other dual cores and to be honest, it doesn't offer any incentive over the other 2nd generation i5's for example.

Intel probably wanted another dual core i7 cpu for marketing purposes.
A lot of people simply don't pay that much attention to the details and end up getting messed over due to their own stupidity.

 

Yes, I'm inclined to agree. Especially if the cores of today can dial back on their power usage when it's not needed. I'm assuming they can, since my old Core Duo (first generation dual core) can go way down to ~500 MHz when demand is low. Then, having the extra ponies under the hood when you might need them is always a nice thing to know.

 

I bought my W520 with the Core i7 2620M because it was cheaper than the quad core, will run cooler and will increase battery life when I'm taxing my W520 on battery.

This is all from a perspective of me not needing the quad core for it's computing power though so everything about it is a negative from my point of view. It really just comes down to what you need, don't get caught up in what a processor CAN do if you won't ever use it to do those things.

 

OK, something to consider. Thanks.

.... but still, won't a dual core 2620 running at native 2.7 GHz tend to run hotter and use more juice than a quad 2720 @ 2.2 GHz?? All things being equal, both cpus/machines running at minimum draw, doesn't the 2.7 GHz naturally pull more power, even at idle?? Seems like it would. Granted, the *max* TDP of the dual core is 35 watts, while the quad is 45 watts, but that is the maximum, not the minimum. At minimum draw, I'd say the 2.2 quad is pulling less power than the 2.7 dual. Or am I missing something??

 

Yes they can, its something called power gating, and that is also the base of the turbo boost. Basically its this:

A program creates processes for it to run its calculations (every program has it)

and every process is one thread, if the program has lets say 1 thread, only one core will do the calculation, if the program has more threads lets say 3, 3 cores will do the processing.

Now since that in the program having 3 process scenario and you have a quad core processor, your processor will shut down one of the cores, no energy is passed to 4th core and it enters a sleep state called S3 (no power at all passed, thus no heat being generated)

Now that we have 3 cores doing the work, and the processor has 4 cores, there is some TDP left.(thermal design power, basically when an electrical current (epd) pass any material the electrons get agitated, thus generate heat, so when a processor works one of the by products is heat, so the TDP is the maximum amount of heat that system is needed to dissipate)

This wiggle room in the TDP is when the turbo boost gets in action, intel calls the increments on the mhz, bins, and since there is some room in the TDP they can put bins in the other cores, thus turbo boost came to life.

This advance in power gating dates to the nehalem architecture.

The i7 2620m is a higher binned processor, and thus its power consumption is lower.

The added memory that it provides is a great for some professionals, since that is the memory that the cpu uses, and when you are doing some complex calculations and the processor needs more memory, the added L3 is an advantage.

The TDP is not the maximum current pulled, this is some terribly wrong concept and only nvidia uses it. for example a clevo P150hm that is equipped with a:

CPU: i7 2630qm, TDP is 45w
GPU: 6970m, TDP is 75w-100w

can consume under load, up to 200w of power, the math dont add up. if power dissipated is equal to the power consumed, then the current pulled would be 145w maximum, if we add the other components like the screen and the drives, they wont pull 55w of power, its impossible, since they consume:

HDD: 5w under load maximum (and this depends on the drive, and this is not something )
Screen: 5-10w under maximum brightness
mobo: 5w-10w

nope as I said the TDP is the heat that needs to be dissipated.

PS: the cores can not only sleep but can also downclock themselves to some great levels

 

@Mr MM: I think I get the idea. Just because a processor is rated at 2.7 or 2.2 GHz does not necessarily mean it will run at such speeds even if "native" mode. Speed-step has taken that issue under control.

Thanks for your perspective. It helps!!

 

Mr MM, the thing that just doesn't add up to me is that wouldn't all the power consumed be dissipated as heat, noise (from the fan), or light (from the screen)? The fan is not very loud, and the screen is not going to put out more light energy than it consumes electricity, so it seems like all the other energy has to go to heat, unless I am totally missing something.

 

What you're 'missing' is that 'other' energy goes to what we want it for (running our systems/programs). Only what can't be directly used for that will be converted to heat.