i7-620m vs. i7-740qm

I know this has been debated about before, but I couldn't really figure out an answer.

But for a gamer, what is more important?
the 620m being able to clock at 3.33 GHz or the 740qm having four cores??

 

Depends what games. 99% of the games you won't see a difference (so I'd go with the i7-620M) while for stuff like GTA 4 the quad will be better.

 

but in a few years, do you think the majority of games will perform better on a quad core?

 

As fred noted, in most games you are not going to see a difference between the two. And unless you run applications that consistently max out the processor (video/audio encoding, photo rendering, math programs, etc) then there will be little to no difference between the processors.

In a few years it is tough to say. Game processor requirements have not increased much over the last four years. Most PC games are console ports from the Xbox 360/PS3; as long as they are around and PC games continue to be console ports, then game system requirements are not going to go up by leaps and bounds. We are fortunate if games effectively use two cores now.

We need a bit more info about what you are doing with the notebook to say one or the other. Namely, how much battery life do you need, etc.

The reason I ask about battery life is because the i5 and i7 dual-core processors have a distinct advantage over the i7 quads: they have built-in integrated graphics. Some notebooks can switch from the dedicated card to the integrated one on-the-fly; see my post here for a full explanation. Combined with the fact a dual-core consumes less power than a quad-core, it saves quite a bit of energy and that can increase your battery life by a lot.

 

since the sager 8690 i'm gonna get has terrible battery life,
it's gonna stay plugged in whenever i use it.

i'm customizing it, and the difference between the two is $20 for the quad core upgrade.
So it seems like it's a good choice...

I like to max out the games I play graphics and resolution wise.
I have crysis and Metro 2033, and I'll keep playing them.
I also occasionally use CS5 and edit some videos on sony vegas..

so why does the dual core i7 max out at 3.33GHz
and the on other only at 2.9?
what are the advantages of a higher speed?

I'm sorry if these questions seem elementary, but I'm not that educated when it comes to computers

 

2 major reasons. The first, and most obvious, is heat. 4 cores make more heat than 2 cores. Let us assume for the sake of argument that heat is linearly related to core speed, so that a core that runs twice as fast is also twice as hot (this is not actually true, but I use this for illustrative purposes). This would mean that for the same heat load, you could run 2 cores twice as fast as 4 cores (considering the whole processor). Now, even while considering that the maximum speeds are just for one core, consider that these CPUs aren't really designed to only run on one core, they're designed for average use of all their cores. It is certainly possible to design the individual cores of the quad for higher performance, but this means you also pay more... which is where the i7-820QM, i7-840QM, i7-920XM, and i7-940XM come in.

The second major reason is that the i7-620M, while based on the same micro-architecture as the quad-cores, is a newer generation with a reduced lithographic process (32 nm Arrandale as opposed to the 45 nm of Clarksfield). This ability to make smaller transistors results in less heat from the CPU components, and thus the ability to "push" them farther and get higher speeds.

As for the advantage of higher speeds, the higher speeds means that the CPU can process instructions more quickly and "think" faster. In general use, however, this is of limited utility; many of the tasks most people do on their computer are not limited by the power of their CPU, in fact, apart from RAM, the CPU is usually the fastest chain in the link of all the components that make up your computer system. In other words, it doesn't matter how fast your CPU is if it's waiting on something else, like a command from you, or fetching information from your HDD, or waiting for your GPU to put something up on the screen. This is why most people say that for current gaming, an i5 is more than enough... most of the time what slows you down in games is not your CPU, but your graphics card.

Now, your CS5 editing and your video editing will probably benefit greatly from a faster/more powerful CPU, as encoding videos and applying graphical effects often take a significant amount of CPU computation. However, as both of those programs tend to be well-threaded programs that take great advantage of multiple cores (at least CS5 is, I'm not as sure about Sony Vegas), in this case you are probably actually better off with four, slightly slower cores than two faster cores, as those programs are more likely to load your CPU to maximum capacity. But for gaming? You're unlikely to notice the difference.

 

thanks judicator.

that was informative and really helped me understand..

I guess nobody knows if programmer will start making games
that take advantage of four cores, but I'll just cross my fingers on this
one and go with the quad.

Thanks for all your help!

 

Games will start utilize multiple cores in a short time.. about 2 years atleast I think. Which means your CPU will be outdated when the time comes, so it won't matter. Dual cores are in the market for a long time however other than servers and workstations, their power isn't even being used efficiently.

Go check some benchmarks and in game FPS logs.
740qm will beat 620m in benchmarks however 620m will have higher FPS in games compared to 740qm.
Why is that? Its because benchmarking softwares are designed in a way to use all available system resources including multiple cores. While games need some instructions to be processed first so other instructions can be processed, NOT at the same time(if 4 cores can't process at the same time, whats the advantage of 4 cores?). Its because proccesses are needed to be completed in a sequence instead of simultaneously AND because game developers are having hard time even supporting dual cores let alone quads.
If you want a quad, go for something better than 740qm. However if your main focus is games, 620m is the best mobile i7 you can get(other than i7 Mobile Extreme CPUs like 920xm/940xm). As a gamer you want raw proccessing power instead of number of cores.

Intel and AMD already have technology for CPUs that have 50 cores or so. You check them on their websites but the main problem is current softwares aren't able to use even 2 cores efficiently.

 

gaming-wise i agree with what people say that most games now will not make use of a quad core.
however most games are usually limited by the gpu and not the cpu, and those few games that are cpu bound seem to be capped by the number of cores more than a cpu's actual speed, ie gta IV, sc2(?). something to think about...

 

Lets say you are in a race where cars carry a load to the finish line to win the race. There are two teams. One has 4 tiny slow cars, one has 2 bigger fast cars. Fast team will finish the race first with the same amount of load. And this is what exactly happens in a game.
A 3.0ghz dual core CPU will beat 3.0ghz quad core CPU, assuming game hasn't been specially optimized for 4 cores. Even thought this is far more real than being an assumption, by the time quad cores are efficiently supported 740qm will be off the game. And note that I'm talking about CPUs of the same clock speed, not even talking about clock speed diffrence between 620m and 740qm.
Its correct 740qm can handle many applications at once, better than 620m. However 740qm will be slower if all those applications require more than 1.73ghz of raw power. Simply because its quad doesn't necessarily mean it is better and faster. If you are going to use photoshop once a while without heavy editing and run games around medium settings, you'll have no problem.
On the other hand 620m is can handle tasks faster. 740qm is really the low-end quad of i7, there is no way you can even compare them.

If this computer is for gaming, go for 620m.
If this is for general use, go for a quad better than 740qm.

 

if we are to take your example then you would be better off with a pentium 3.0ghz

imho both cpus will do just fine for you. and iirc the 720qm will use an 18x multiplier when in 2 core mode giving it 2.4ghz and a 740qm is .13ghz faster than the 720. as you see the difference between them and the 620 is not as big as some would put it.
in fact for pure gaming the 540 or 520 would be the best bang for buck

 

I would add then "assuming same CPU architecture" to complete his analogy.

 

yeah that sounds more correct.

 

i gave incomplete data in my example above. in 2 core mode this how they stack up:
740qm 2.53ghz
620m 2.96ghz
so there is a difference in 2 core mode, however it becomes trickier to compare them since the 740qm has 50% bigger l2 cache and 33% bigger l3, 30% faster bus, and an on-die memory controller as opposed to the 620m's on package memory controller

 

I find this analogy slightly flawed in some details, although basically sound. For one, why are the 4 cars smaller than the 2 cars? I don't believe that an individual core from a quad-core is significantly less capable than an individual core from a dual-core, apart from processor speed, which is already accounted for by the speed of the car in your example. And yes, in your example, if the load is less than the capacity of 2 cars, then certainly, the faster 2 cars will beat out the slower 4 cars, but if the load happens to be greater than the capacity of 2 cars, then because the 2 cars have to make an extra trip, it's quite possible that the 4 cars will then beat out the 2 (depending on actual speed difference of the cars at that point). This also points out the importance of how much the load can be split into individual threads at that point; if the load could only be split into, say, 3 parts, and 2 of those parts together was more than the capacity of a single car, then the 2 car dual-core would still have to make an extra trip, just because of the way the load is broken down.

Also, how can a 3.0 GHz dual-core beat a 3.0 GHz quad-core, assuming those are base clocks and the same generation technology? The only reason the i7-620M beats out the i7-740QM (or even the older i7-720QM) is _because_ it's clocked faster; if they were both clocked at the same speed, the quad would beat out the dual in everything except heat and power consumption (well, and the fact that it has no integrated GPU, but that's not really relevant to our current discussion).

Your second to last paragraph is not too far off, although I'll point out that if you're multitasking so much that the quad-core is choking, the dual-core will choke just as badly, mainly because that level of multitasking means you have many threads going, which are more easily split up among the 4 cores than just 2 cores. Now if the quad core is choking on a few heavy threads, then yes, the dual-core will come out on top.

Really, in the i7-620M vs the i7-740QM race, I'd say that unless you have certain specialized requirements like video-editing, just go for whichever one is cheaper. While you may get a few FPS advantage in using an i7-620M compared to an i7-740QM, I doubt it'll usually be that noticeable.

 

@Judicator: Uhh... Exactly what I have been speculating... I have to tell DELL about my replacement choice b/w 1645 (i7-740QM) vs 1647 (i7-620M).

I am thinking of going with the 1645 (with 1GB DDR3 ATI Mobility Radeon HD 5730) as my main aim is a generic system - basically running VMWARE machines for development / sound editing / photo-shopping / moderate gaming (Half Life/GTA/CRISIS and so on)

Should I place my bet on the 1645 (with the 740QM)?

Let me know please, Thanks!

CK

 

i stronlgy suggest u get a quad.. its future proof , plus many games now need quads as a minimum.. like GTA IV , Battlefield BC2 , Metro 2033 need quads.

 

Especially with the VMWARE and possibly the photo-shopping, you'll almost certainly want the i7-740QM. GTA will also prefer the quad-core (due to coding issues). The only thing to watch out for is that I think the 1645 is known to run rather hot as is, which might put some limits on exactly how far you can push your machine. The 1647 might run cooler (you'd have to check with others, possibly in the Dell subforum), which might in the end let it run better than the 1645, but that's really more due to the notebook itself and it's cooling rather than any actual limitation of the CPUs themselves.

 

as i suggested in the other thread, ask around in the dell subforums as the power/performance of a 740qm would be useless if the laptop is unable to handle the thermal load.

 

I'm quite sure the 1645 can take it.. the only issues were throttling issues which were fixed by bigger power adapter.

 

if thats the case, then your all set. just get a bigger psu

 

But all those things really don't make much difference. Also, on-die and on-package doesn't mean anything since they communicate with each other just the same.

 

im sure the the larger cache and faster bus will make a difference.
i also read somewhere that on die does make a difference.
i think sandybridge is moving towards on die too (cmiiw)

 

Cache suffers from diminishing returns very rapidly and in most applications doesn't show an improvement. The faster bus means little since the bus is not bottlenecking anything. If it was, having ram in single channel would show drastic reductions in performance versus dual channel, but it doesn't show much of a difference if it shows any at all. Lastly, yes, an on-die memory controller can make a huge difference, a la AMD Athlon XP to Athlon 64. In this case, however, just because the memory controller is not on the same piece of silicon as the processing cores does not mean it is inferior to "on-die." In all practical senses, it is the same thing. There is no difference because it communicates with the rest of the chip the same as if it were on the same piece of silicon. It is exactly like the core 2 quad cores, where they use two separate dual core pieces of silicon, or pentium pros, where their l2 cache is on a separate piece of silicon, yet that makes no difference whatsoever.

 

It depends entirely what your primary use for the computer will be. The 620M is a newer processor with a better architecture / lower nm process when compared to the 740QM. It also has a higher clock speed making it perfect for current game titles.

If it is indeed games that you are worried about when choosing the CPU, i would definatly pick the 620M, the main reason being that by the time games programmed with quad core instruction sets are ACTUALLY released the on-board GPU of your laptop will be obsolete (because of obvious advances in graphics technology / requirements to play newer games) thus rendering it pointless to chose the quad in the interim.

If you are looking at doing both gaming and digital rendering (for example with CS5) i would still pick the 620M as the combination of increased clock speed combined with a newer instruction set places it in an almost identical position as the 740QM when running in turbo mode (various benchmarks confirm this). In addition, you should chose a mid-to-high end GPU option such as the 5850M as this will benefit you for both gaming and digital rendering on CS5 as both CS4 and CS5 support accelerated rendering by pulling resources from your GPU.

If you are looking for only using the laptop for digital rendering / multi-core applications and not for gaming, you should ideally be looking at a higher model Intel quad or else perhaps a high end AMD quad.

Chris

 

the arrandales have a new instruction set.

 

imo having all three; better cache, faster bus and an on-die controller, is def an advantage. i think the question is it enough to offset the disparity in clock speed.
like many have said i think it all boils down to what you want to do.