T520 i7-2620M vs i7-2720QM for basic office use.

[wwcanoer]

I will buy a T520 and want to know whether the I7-2620M or 2720QM is better for me. (The QM is only $35 more.)

i7-2620M: 2-core 2.70GHz, 4MB L3 (Max SC/DC/QC Turbo 3.4, 3.2, n/a GHz)
i7-2720QM: 4-core 2.20GHz, 6MB L3 (Max SC/DC/QC Turbo 3.3, 3.2, 3.0 GHz)

My use: Win 7, primarily MS Office documents, creating pdfs, internet browsing with many windows. (No significant image/video/CAD use.) I find my X61 tablet slow: Core2Duo L7500 1.60GHz, Vista, 4GB RAM.

Therefore, is the 2-core better for me? Or will basic use still benefit from the 4-core? i.e. Will even basic programs now benefit from the extra cores or are they useless if not using a high-intensity program designed for them?

The main disadvantage of the 4-core is the increased power consumption and presumably heat & fan noise. Will there always be a higher power consumption than a 2-core, or only when there is intensive use of all 4 cores?

Thanks in advance.

========== FYI REFERENCES ===========
CPU Comparison - Specifications
http://www.anandtech.com/show/4084/inte ... -landscape
http://www.cpu-world.com/Compare/569/In ... GA%29.html

CPU Comparison - Tests - Little difference on some tests, large difference on others.

CPU Benchmark:
2620M = 3941: http://www.cpubenchmark.net/cpu.php?cpu ... 40+2.70GHz
2720QM = 7140: http://www.cpubenchmark.net/cpu.php?cpu ... 40+2.20GHz

Many Benchmarks:
http://www.notebookcheck.net/Mobile-Pro ... prime_32=1

[jvarszegi]

Either is essentially overkill, so I guess the best answer is, "It doesn't matter between those two processors". You can save a fair amount of money by going with a lower-spec i5 or even an i3 processor, which will be a speed demon compared to your X61 and satisfy all of your stated computing needs quite handily.

[ZaZ]

If you're looking for a performance increase, a good SSD is probably a better path to it than a couple extra cores since nothing you're doing is particularly CPU intensive.

[Q-Ball]

Seeing as you're from Switzerland:

If those two laptops are your only two options, the choice really is yours. There isn't any difference in the boards like there is with the W520 (the quad-core T520s still only have 2 RAM slots).
Windows doesn't really use quad-core processors to their fullest potential: but the factor to consider here is the Turbo Boost- single and dual core operations should be accelerated to the same speed as the 2620M under ideal conditions.
The fan speeds shouldn't be any different.
Battery life should be functionally identical- a W520 with a 9-cell battery (loaded with a 2720QM and Quadro 2000M) can get 7 hours of casual use (i.e. video playback from hard disk) with a new battery, so the T520 should last longer than that regardless of processor choice.

But one thing to note is that the quad-core T520 comes with a larger, heftier power brick (the 135W) instead of the smaller 90W that the dual-core model comes with.



If those two models aren't the only ones you can get, get a T520i with a Core i3 processor, or a T520 with the slowest (relative) processor, and buy an SSD.

Intel (X25-V/M/E, 310, 320, 510), Crucial/Micron (C300, m4), and Samsung (470, 830) models are currently the most reliable brands to get.
If you can't get any of those, steer clear of SATA 6Gb/s SandForce drives and OCZ in general. (The older generation of SandForce drives are more reliable than the new ones are.)

[wwcanoer]

Thank you all for you input.

Does anyone think that the 2.2 GHz 4-core could be slower that the 2.7 GHz 2-core for basic tasks, or will both smoothly ramp to the 3.2/3.4 GHz turbo when required and thus act the same?

Unless there is a risk of the QM being slower, I will probably risk the extra $30 to go for the QM since from another thread, it was confirmed that a 90W adapter can be used with the T520 4-core. http://forum.thinkpads.com/viewtopic.ph ... 19&start=0

My next expansion would be adding an mSATA SSD for the boot drive and most active working files, thereby keeping the DVD and 500GB HDD for longer term storage and back-ups.

FYI: Currently, dropping from i7-2620m to i5-2520 saves only $190 - 15% discount by phone = $161, which is significant, but yet only 15% of the notebook cost, so for me, it is worth it to know that CPU will not be a limiting factor and will last me for a few years. Heck, the dock alone is nearly $300, so the CPU upgrade is a small part of the total investment.

FYI: In Switzerland I can only buy selected pre-configured systems. To customize one (i.e. to get English windows & keyboard), I need to buy from Germany, France or UK but it is much cheaper and simpler for me to buy in USA and have a friend to ship it to me in Switzerland.

[ZaZ]

Even a i3 would be almost three times as fast as your L7500. If you're not doing anything CPU intensive, the i7 will be no better than a i3. How does your X61t seem slow? Could be the slow hard drive, which is why a SSD would help more than a CPU upgrade. My R60e, which is five years older, often feels faster than my X220i because it's got a SSD and it runs Linux.

[HLG600]

Hard drive, as the others mentioned, and RAM. Those are the real bottlenecks, not so much the processor...at least for basic computing.

[antskip]

All this discussion over $35? Don't even think about it - just get the quad.

[jvarszegi]

All this discussion over $35? Don't even think about it - just get the quad.

For what purpose? I think the OP'd be better off saving literally hundreds of dollars and downgrading to at least an i5. He/she simply won't see any benefit from a quad-core, especially if it hampers the ability to use smaller power adapters.

[wwcanoer]

Though I can understand that an i5 should be enough now, I am concerned that it too will soon feel slow... and then when I need a new one, I will need a new dock for the new models etc... and in the longer run there will be no savings because I don't tend to sell my old ones...

My core question is that, given there is essentially no price difference, is a 2.2 GHz quad as fast as a 2.7 GHz dual when using basic windows apps.

The common answer seems to be:
- ignore the GHz speed difference and go quad
- it would not matter anyways since both are too fast.

There are few differences between the CPUs:
http://ark.intel.com/compare/50067,52231
Quad / Dual
2.2 - 3.3 GHz / 2.7 - 3.4 GHz
6MB / 4 MB cache
45W / 35 W
DDR3-1600 / DDR3-1333
16GB / 8 GB max
25.6 GB/s vs 21.3 GB/s Max memory bandwidth.

[sir_synthsalot]

Quad is 45W TDP so it will be hotter and louder, depending on how well Lenovo designed the cooling system, and probably have lower battery life. I would go with an i5 or the i7 quad if you're really paranoid about performance since those ones probably have a better bang for the buck than the dual core i7.

For basic office activities I would get a core i5 and not think twice about it. Windows 8 will have the same system requirements as Windows 7. For web browsing they are always trying to make the browser faster and use less memory than the other guy's browser. I just don't really see it getting outdated and slow very quickly.

[wwcanoer]

My theory is that for the same software actions/load, the QM may run quieter because
1) I am assuming that at the same software load, there would be approximately the same heat created in both. (Perhaps slightly more overhead in the QM since it can only run one core to 3.3 GHz compare to the M's 3.4 GHz)
2) Since it must handle 45W over 35W, the QM cooling system is likely more capable (ex larger heat sink) and so the fan may actually run slower on the QM when for the same software load.

Another benefit may be that since QM has more heat/power room/capability, it may be able to run in "turbo" mode more often and longer than an M. (i.e. the QM could run 2-cores up to 45W total whereas the M can only run its 2-cores up to 35 W, so the QM may be able to stay at 3.2 GHz longer)

With 2 cores active, both have the same 3.2 GHz limit. Since the CPUs are so similar, it may be that the QM can run 2 cores at 2.7 GHz as comfortably as the M. It only has the lower 2.2 GHz rating because when running 4-cores simultaneously, it can only handle the heat (or some other limit) at 2.2 GHz.

However, the many benchmarks test showed the QM faster on some single core tests and slower than others:
http://www.notebookcheck.net/Mobile-Pro ... prime_32=1

Only a theory (guess).

[wwcanoer]

My conclusion is that I will go 4-core (QM) because there appears to be no fear of it being slower due to the 2.2 GHz rating.

Why does my computer slow down? I don't know. However, there are a few programs that do cause noticeable problems, like box sync from filehost box.net. Whenever there are a lot changed files (10 or more), my computer response nose-dives for an extended period. The files are not large (max 20 page pdf) so I don't understand why it does this. Though new releases have been acting better, I hope that being able to assign this program to core #4 so that it does not disrupt cores 1 & 2 (assuming these are what what windows uses first by default) would really help. I would do this for my regular backup and sync programs as well. This explain how: http://btoforums.com/showthread.php?t=2875 Of course, I will first see how windows 7 manages on its own.

Intel advertises that multiple cores will allow anti-virus and such to run less obtrusively on another core. I hope they are correct.

Thank you to all for your input.

[wwcanoer]

Yesterday, for the T520 Lenovo has
replaced Intel Core i7-2720QM Processor (2.20GHz, 6MB L3, 1333MHz FSB, 3.30GHz Turbo)
with the Intel Core i7-2760QM Processor (2.40GHz, 6MB L3, 1333MHz FSB, 3.50GHz Turbo)
at the same price!

Luckily I did not order mine yet. Since there can be almost no question that the i7-2760QM is faster than the dual core:
Intel Core i7-2620M Processor (2.70GHz, 4MB L3, 1333MHz FSB, 3.40GHz Turbo)

Note: The Lenovo site states 2760QM 8MB cache but the Intel specs says 6 MB cache.

Note: The Intel compare sheet says the 2760QM does not have these 2 features that the 2720QM has.
- Intel® HD Graphics No
- Intel® HD Graphics with Dynamic Frequency No
But I believe that is a typo as well because the individual spec sheet states that it has Intel® HD Graphics 3000 and that "Graphics Base Frequency = 650 MHz; Graphics Max Dynamic Frequency = 1.3 GHz"

REF:
http://ark.intel.com/products/53474/Int ... _40-GHz%29
http://ark.intel.com/products/series/53251
http://www.intel.com/content/www/us/en/ ... ssors.html

[jvarszegi]

I'm glad you're happy, but I've never seen a user of basic Office etc. stress out so much over getting the fastest available processors! I wouldn't worry at all and just order a machine. Otherwise, you're going to wait forever. You really won't see any difference you will notice at all for your stated uses, probably going all the way down to the i3 processor. Just buy a laptop and end your misery.

[wwcanoer]

No misery.

{ FYI: It took some time because my first Lenovo phone sales rep, who gave me a quote for a little better than 15% off of the web price (compared to only 10% off via the web coupon), did not respond to my email request to change the M to QM and her phone number did not work. So after waiting 3 days, I phoned again and another fellow updated the quote to QM and matched the discount but then I noticed an error, which he fixed yesterday, but this morning when I when I went to actually execute the purchase I checked the current price and noticed the better processor, so I will get that changed and buy it later today. }