The new Intel Core i7 740QM / 840QM / 940XM vs 720QM / 820QM / 920XM (+Benchmark)

[Aikimox]

Not @ max boost. They both equalize @3.2ghz. And since most games still benefit from the raw single/dual core power - you won't see a difference. The Notebookcheck's review only shows 1-2FPS difference in a few games they compared.
Now add the lower TDP and with the 840QM you have more headroom for OC'ing the GPU's

[lackofcheese]

Max boost is single-core only, while quite a few games will use two cores, and some will use more. Also, the main issue between these CPUs isn't gaming performance anyway - spending that much money on a CPU for gaming alone is hard to justify. Granted, if you're not using the unlocked multipliers, you're still spending a lot on the 133MHz difference between the two, since that's only a 6.25% difference (and that's on four cores, where the 133MHz will make the most difference).

As for the TDP, that's just a label. The power consumption of the i7-840QM will likely be closer to the i7-920XM than it is to the i7-720QM, despite having the same official TDP as the latter.

[Aikimox]

Spending that much money on a CPU for non-gaming reasons is even more ridiculous For benching? Lol, yeah.
For video encoding? You will not feel much difference there as well. What remains, - VT? There, regardless of your rig, the system will agonize when running multiple OS instances. All in all I can justify gaming more than anything else.

Now for the TDP. If we trust their tests, the power consumption difference is ~10-15W between the two.
And even if it was less, I'd still point you to the OC'ers threads to see that every single watt matters at times

[lackofcheese]

Yes, it's obvious that most of the higher Core i5s and i7s are overpriced; the i7-820QM and above are where it gets worse.

Nonetheless, even compared to a Core i5 the performance difference in most games will be very slight. Tasks like video encoding are probably the best use for a quad-core CPU, but the mobile quad-cores sacrifice a lot of clock speed to meet the heat/power limitations of a laptop, which weakens their advantage in that regard.

In any case, if we're talking about gaming alone, there's little justification for going above a Core i5 based on pricing.

Looking at the Notebookjournal results, it looks like TDPs might be more representative than I expected. It's strange that such a large jump in power consumption would occur with only a slight jump in clock speed, though.

[Aikimox]

I agree, i5 is enough for most games. Dual core i7-620M actually outperforms the quad 720QM in many scenarios. The upcoming i5-580M will boost to 3.3GHz - awesome performance without burning a hole in your wallet.

TDP:

The difference gets most apparent during the stress test with prime95, which fully loads all available cores. Here, the two Extreme processors require about 20W more.

This is strange indeed. The difference should appear when OC'ing the extreme CPU's but as far as I understand the testing system had no OC'ing options available in BIOS.

[nobodyshero]

I agree, i5 is enough for most games. Dual core i7-620M actually outperforms the quad 720QM in many scenarios. The upcoming i5-580M will boost to 3.3GHz - awesome performance without burning a hole in your wallet.

Wow. Sooooo tempting to grab a i5-580 laptop before high end SB arrives in Q2. I've waited a year, what's another half a year though for SB

[lackofcheese]

The i5-580M looks like an i7-620M with only 3MB of L3 cache. The release price needs to be below $300, though. Depending on how competitive the pricing is, I'd consider upgrading the i5-430M in my GX640.

[KipCoo]

In benchmarks you will see a slight improvement going from a 920XM but in gaming virtually none.
One very good thing about these new chips is the price drope of the "old" ones.
You can find brand new OEM 920XM's for around $699, yeah that's still a lot of money but a few months back you couldn't find one for under $1000.
I say it's a win win situation either way

$699 where?

[Daniel Hahn]

$699 where?

Good question, at least the 920XM ES/QS is almost half as expensive as the 940XM ES/QS.

[The Revelator]

This is strange indeed. The difference should appear when OC'ing the extreme CPU's but as far as I understand the testing system had no OC'ing options available in BIOS.

From the article:

"In the BIOS of our test device can be four levels to choose. For the tests we have chosen the maximum overclocking. This is a Core i7 940XM then with clock speeds from 2.3 to 3.8 GHz. Necessary but is a notebook with a good cooling system and a strong enough power supply. In the case of the W870CU but that is no problem. The price of Intel's mobile Extreme-top models, however, is exorbitantly high."

The test bed is another one of the mySN W870CU's with the unlocked BIOS that we've been chasing for several months. Among other things, it permits increasing the multipliers by 4x. The unlocked BIOS seems to be the same one that was used with the original Sager 8760's but replaced soon thereafter when revised to recognize the 5870. Purported copies of the mySN BIOS show up on the Net periodically, but so far have been bogus, i.e., not unlocked. They seem to be used primarily for review samples.