i7 620M vs. 720QM

Any benchmarks, reviews yet?

I'm planning on buying a NB and I'm deciding between these two. I know that this is a comparison of quad vs. dual and it has been discussed many times, what I'd like to know is if the difference in working frequency and while TB is on will have any impact on performance.

Enlighten me please...

EDIT: Added poll...

 

Depends on what you plan to use it for. For my usage pattern (development) the 620M is the better choice:
- Lower heat loss (32nm vs 45nm, dual vers quad core)
- Higher maximum instructions/second due to higher frequency
- The build process (compiler/linker) has too many dependencies and more cores do not speed up things linearly. E.g. linker/compiler cannot take full advantage of the 4 cores.

However if your application (e.g. games) can take full advantage of the additional cores and you don't mind the additional heat loss, a quad core might be the better choice.

Regards,
Mat

 

A bit more information then... Laptop in question is Clevo 860CU. It will be used for gaming, internet and other general stuff. But mainly I'm looking for the one that will be better for gaming, other stuff is secondarily. I don't mind the heat.
Thanks

 

I think they will be pretty close, even in heavily multi-threaded apps. In lightly multi-threaded apps, it'll be 620M that's faster, no question. But with many threads, its 100% more cores vs. 77% more frequency.

Clock speed advantages of 620M over 720QM factoring in Turbo Mode.

1 thread-19%
2 thread-27.5%
4+ threads-77%

But is the 720QM worth it for massive TDP differences and heat? In my mind, the top 3 i7s(that are relevant) are now 920XM, 820QM and 620M.

 

i would go with 620m. laptop tdp is makes a big difference in battery life and heat generated. Plus I am not sure turbo mode works for every load. Raw cpu speed would ultimately work better when you are doing more than 2 tasks.

I am hoping sandy bridge cpu's have lower tdp quad cores and at higher base cpu speed as well.until then arrandale would be better buys unless you are looking at DTR.

 

Would the quad core be faster for extracting large winrar files around 10GB?

 

If winrar (or whatever extracting program you use) allow for multi-threading.

 

Isn't that primarily limited by your HDD speed?

 

QuadAllegory,

Yes, the HD speed would be one limiting factor, but WinRAR does support a multi threaded CPU, so it is faster the more cores you have (don't know if it does more than two though, I should test this tomorrow).

 

Do you have both the quad core and dual core i7? That would be great if you could do a test. How do the wprime times compare?

 

worx,

No, no i7, just wanted to verify it on my quad. Sorry!

 

Soo, better choice would be 620M, right?

 

I wish there were some benchmarks out to see the performance and battery life comparisons.

 

I think the 720QM for gaming, more and more games are making use of all the cores. the i7 efficiency is really good .

I take it if your gaming, your not exactly going to overdo the "mobile" side to laptops? So battery life can be a secondary concideration.

 

Just to point out there is not much power saving between 45nm and 32nm atm since the 32nm is quite leaky atm.

 

Does the 620m include built in graphics? Can it be switched to use integrated graphics vs dedicated graphics to save battery life?

 

I don't really care about battery life because I use my laptop as a desktop. Battery is out of the laptop all the time.

 

Added poll...

Also I read this somewhere

One more thing, 720QM supports 1333 memory and 620M supportso only 1066. What is the difference then? How big?

 

There is more to worry about then just the application. There are background processes and if you run more then one application a quad core will help. The reason I want/need a quad core CPU is not because I have some multi-threaded application, rather to help take care of stuff in the background with cpu power left over for the main application and all the many others that are running as well.

But if all you do is open 1 thing and try to maximize one application then the dual core is your ticket.

 

Memory speed makes no difference. If you don't care about battery life and are planning on using your notebook as a desktop replacement, get the quad core i7.

 

I would add that the I7 has hyper-threading dual core should have hyperthreading so background apps will still have a couple of logical cores to play with.

That said the quad is only about 15% slower in single thread stuff and there is plenty of stuff that will scale to 4 cores. Its also no bad thing to get the slowest of a new generation, there are limits to how high the clock can ramp so its unlikely we will see 5ghz dual cores but we may well see 3gz quads/octs that are socket compatible in a year or so that would offer a nice upgrade.

Personally im going for a quad as they currently run hotter so need better cooling, 18 months time i can pick up some 35nm monster of ebay and know the cooling can handle it.

 

Aren't sockets the same for those two CPUs?

 

Sockets are, yes. Given a supporting BIOS, you can actually drop an Arrandale into one of the (current) i7 motherboards with no problem at all; the issue will be whether or not that motherboard has the necessary addons to support the IGP (if it doesn't, all you get is the dual-core processor).

 

IDK, chipset is PM55 and there is already an option for both CPUs, so I guess the support is there...

 

Not necessarily. It seems like it will depend on which PM55 revision (stepping) you have.

http://www.fudzilla.com/content/view/16517/35/

Additionally, PM55 is just a chipset, so even if the chipset supports it, the motherboard containing the chipset might not connect the links for the IGP...

 

Okay, some numbers for a quad core Q9450 and unraring an 5.43GB 7z file to 8.06GB uncompressed with WinRAR 3.80 and 3.91:

On a 300GB VRaptor (7z file located and uncompressed to same drive)

WinRAR 3.80 12 Minutes (Four cores used avg: 50%)

WinRAR 3.91 11 Minutes 15 Seconds (Four cores 50%)


WinRAR 3.8: 19.186 MB/s conversion speed

WinRAR 3.91: 20.929 MB/s conversion speed


Was expecting more of a performance increase, but 9% by simply using different versions of the same software is welcome. Was expecting more because I thought v3.8 was not using multiple cores, but I was wrong.

What is most interesting is that not only are the MB/s results way below the VRaptor's performance envelope, but the VRaptor with WinRAR 3.80 was also faster by itself than using two 74GB Raptors using WinRAR 3.91 (one holding the 7z file and one being extracted to - total time 12:14 MM:SS).

Now, an SSD with their superior read speeds would certainly speed this 'test' up (I'm sure the CPU's were starved for data), but I'm curious if anybody can do a similar test on their i7 (any version) vs. an available quad they may have access to?

Would be very telling of one aspect of the 'real world' performance differences between yesterday's quads and today's i7's.

Cheers!

 

Thanks. One thing just to make it clear, if the motherboard already supports these Arrandales, does that means that it has been already updated to B3 stepping and supports new features?

 

So if I buy an i5 laptop, do you think I could install the i7 Quad if the BIOS supports it?

 

Yes. Look at Alienware's M15x. You have your choice of i5 540m and i7 dual/quads. Cooling on the other hand may be an issue going from a system designed for a 35 watt TDP 540m to a 55 watt TDP 920xm. Same PGA988 socket.

 

I would say yes to the stepping, and possibly to the new features. The problem is, really, it all depends on the notebook manufacturer. Just because the new feature is there in the chipset does not mean that the manufacturer bothers to hook it up. An example of this are some of the older Core 2 Sony notebooks; even when the processor supported hardware virtualization, Sony deliberately disabled it in their BIOS. If an Arrandale equipped notebook comes with a discreet GPU, the manufacturer may not bother using the integrated Arrandale GPU, whether due to not wanting to deal with the headaches of designing the motherboard to accept switchable graphics, or whatnot.

 

I have no idea how many games are currently using multiple cores so maybe a good 2 core cpu is still better for my gaming purposes.

 

Thanks for clearing that up.

But when buying, you're not buying for today, you have to think in advance. Probably more and more games will support more cores. And the difference is 10€.
Anyway I think I'm still going to wait for some benchmarks.

 

grbac, I think the number of cores a processor has will remain relatively unimportant for considerable time in the (gaming) laptop market. The limiting factor/bottleneck when gaming on laptops is usually the GPU. And I don't expect that to change anytime soon. With a CPU as fast as a Core i7-620M, you'll be GPU-limited in 90%+ of games. Even if your GPU is fairly high-end.

 

GPU will be 280M.

 

i would just get the quad.. its gonna be faster anyways even with slower speed.... 8 threads beat 4... and 4 cores beat 2.

 

The support team where I'm planning to order the NB said that they already did some benchmarking and according to them quad is better.

 

Go for the Arrandale. On board IGP and smaller CPU are good things to have, not to mention cheaper and less power hungry (less heat) and does all more than fine. C2D does all fine, Arrandale does it better, Clarksfield is an over-overkill, I would know...I have seen very rarely my 720QM hit the 30% doing loads of stuff...

 

Sounds like the dual core would perform better most of the time, with the quad core only performing better with apps that take advantage of ALL 4 cores.

 

What do you mean - overkill, it's not used up to it's potential? Maybe not now, but in the future...

 

Ehm, a gaming laptop only lasts like 2 years anyway since the gpu is the biggest bottleneck as most people here already said.
I just need to know if the current games are mostly going to run on 2 cores, and if so, if the cheaper cpu isn't better to run them because it has a higher clockrate.

 

The difference in price between these two are 10euros, somewhere is even the same price.

Also the difference is in "DMI 4.8 GT/s and Max Memory Bandwidth 17.1 GB/s " for 620M compared to "DMI 2.5 GT/s and Max Memory Bandwidth 21 GB/s " for 720QM.
And quad also supports 1333memory, somebody here mentioned that this is no big difference. Dual also has Thermal Monitoring Technologies, AES New Instructions, dunno what is all this or what gains does it bring.

I asked the support team to provide me with some benchmarks if they can. Maybe they will be so good to do so.

 

In France, you need add 170euros (245$) from 720QM to 620M !

Btw, Arrandale supports 1066 mhz officialy but it supports 1333 with no problem. Just look the M15x with i7 720QM (the memory controller supports officialy 1333 max) and you can up to the DDR3 1600 in the bios.

Dell France ships the the M15x i7 620M with DDR3 frequency to 1333 Mhz.

 

Are you saying that Arrandale can support DDR3-1600 without downclocking the RAM? That's phenomenal.

Otherwise, just about any computer can use memory of a compatible type at any speed. You can pair DDR2-800 with a Dothan Pentium M, so by your logic it would be fully supported.

 

I don't understand sorry.

Why you want downclock the ram for UP to DDR3-1600 ?

With Arrandale, if you bios allows to up the DDR3 frequency (M15x allows to up the DDR3 frequency with i7 720QM from 1066 or 1333 to 1600 and probaly the same with Arrandale CPU), you can set highter DDR3 frequency.

M15x in France with Arrandale CPU is ships with 1333 Mhz and the bios is the same of M15x Clarksfield (just add CPU Support Arrandale in the BIOS), so I think Dell up the DDR3 frequency to 1333 in the BIOS.

 

I mean that Arrandale is an overkill most of the time. Clarksfield is an exaggeration. Mostly wasted unless you are really going to take advantage of multi-core applications. Games can run well on dual cores, and remember Arrandale can work as a quad too. My vote goes for Arrandale, it is cooler, has the IGP, and suits all needs.

France has overpriced technology in general. Quite annoying I would say...I'm looking for a good HDTV and they are quite expensive...grrr

 

Oh yes...

For M15x with my option, it costs 2700$ on the Dell US site.

In France, exactly same M15x option, it costs 3900$ (2700€

 

The Envy costs here 1200 euros compared to the 1800 it was when I got it, but in France HP has disgraced us, whit a WXGA...they dont think we are worthy of the WUXGA and the 6GB RAM....:S

BTW, great upgrade. From Studio XPS 1645 to M15x...not bad at all. Good luck!

Anyways, back to topic. I vote for the newer technology. Clarksfield in fact was known to be just a "stand by" for Arrandale to come...

 

Hehe But it's not finaly yet. Because Dell called me back to tell me that there is probaly an uncompatibility between i7 620 and GTX 260M.

I'm waiting Monday for the reponse of marketing service

If it's the case, I'm going for the i7 QM and GTX260M because i7 620 and the bad GT 240M for this price......

 

I found this site that list some programs that uses 4 cores.

 

Why don't we just do some simple math? I have no idea what the performance per clock is for these two CPUs, or what triggers their turbo modes.

Total ghz for apps that can take advantage of 4 cores:
620M 5.32ghz (6.12ghz dual core turbo)
720M 6.4ghz (6.92ghz quad core turbo)

Total ghz for apps that an take advantage of 2 cores:
620M 5.32ghz (6.12ghz dual core turbo)
720M 3.2ghz (4.8ghz dual core turbo)

Total ghz for apps that can take advantage of 1 core:
620M 2.66ghz (3.33ghz single core turbo)
720M 1.6ghz (2.80ghz single core turbo)