Dear lazyweb: To i7 or not to i7?

28 October 2009

So, my home laptop is finally on its last legs. I’m sure a full reinstall would help, but to be honest now that I’m playing with WebGL and now OpenCL (a new standard for number-crunching using graphics cards, which sounds like it has interesting Resolver One possibilities) has appeared, a Centrino Pentium M at 1.6Ghz and a crappy Intel graphics card really won’t cut the mustard. Add on to that the fact that I’m dropping my home desktop machine and becoming a laptop-only person, and it’s really time to change.

The most tempting lappy out there for me is the Dell Studio XPS 16, which is extremely high-specced, has a very well-reviewed screen, and has what looks to me like an underpriced SSD upgrade (£240 upgrades you from a 500GB 7,200rpm drive to a 256GB SSD). The only downside I’ve noted is that apparently they run quite hot, but so long as I keep it on the arm of my armchair or on the desk, the risks should be minimal.

My big question is, though, which processor? I don’t want a fully-loaded system (largely because I can’t afford it) so the choice appears to be between a Core 2 Duo T9600 (2.80Ghz, 1066MHz FSB, 6MB cache) or a i7 720QM (1.60Ghz, 1333MHz FSB, 6MB cache). They’re pretty much the same price. The i7, when running single-threaded code, overclocks itself using Intel’s “Turbo Boost” and runs at 2.8Ghz anyway. And the benchmarks are better for the i7, so while it’s hard to work out what’s likely to be best for my ultimate usage patterns, the i7 looks most likely to win out speedwise. OTOH it consumes more power, which means that (a) battery life will be worse and (b) the heat problems that people have mentioned will be worse. And I’d rather not have a laptop that turns into a small puddle of silicon while I’m using it, bringing the Thomas line to a premature close — or that, alternatively, makes a noise like a jet fighter taking off every time I run something computationally non-trivial.

Sadly, googling for comparisons between the CPUs (even after filtering out all the spammy “shopping comparison sites”) didn’t really lead to anything useful to help me make a decision. So, does anyone reading here have any ideas?

[UPDATE] I got the i7.

4 thoughts on “Dear lazyweb: To i7 or not to i7?

  1. Michael Foord

    Make sure you post a follow up when you decide. :-)

    It seems like the i5 / i7 processors are the first interesting thing to happen to laptops since the introduction of the Core Duo 2 range.

  2. Greg Bray

    I’ve recently purchased two new i7 based desktops, and my overall opinion is that they are well worth the extra investment if you plan to keep the machine for 4-5 years. Be aware that the i5 and i7 models differ from part to part: Some don’t have hyper-threading and some have better support for virtualization. In the desktop world there is also two different versions of i7: the “enthusiast” parts are more expensive ($300-$1000), use a LGA1366 socket, the X58 chipset, and have an integrated 3 channel memory controller, where as the new i5/i7 consumer models are a bit cheaper ($200-$300), use a LGA1156 socket, the P55 chipset, and an integrated 2 channel memory controller. If you plan on building a beefy machine and want to run multiple VMs, then an i7 chip with 64bit OS and 6-8GB ram is well worth the investment.

    I haven’t played with the mobile versions yet, but I am very impressed with the enthusiast i7 920 and consumer i7 860. The consumer chips offer a lot more bang for the buck, and will probably replace the Core Duo 2 line over the next year or two. Also the turbo boost can actually help save battery power, since the newer versions use a very aggressive form of clock speed management to only use full power when needed. Combine that with Windows 7, which will park idle cores at low power until they are needed, and you should be able to squeeze extra life out of the battery.

    If they are the same price, I would take the i7. If you plan on doing anything cpu intensive or anything with virtual machines, then you are looking at 2 single threaded cores with the T9600 vs 4 hyperthreaded cores with the i7. Here are a few links to help you choose:

    Intel T9600 and i7-720QM comparison – http://ark.intel.com/Compare.aspx?ids=35563,43122,

    Review of i7 Mobile chips – http://www.legitreviews.com/article/1084/1/

    Review of new i5/i7 chips – http://www.legitreviews.com/article/1060/1/

    Turbo Boost when running a Resolver One Workbook :-P http://tiny.cc/Vz3aW

    Windows 7 parked cores in Resource Monitor – http://tiny.cc/ZKINI

    Hope that helps!

  3. giles Post author

    Greg,

    Wow, thank you for posting so much! That’s really useful stuff, and pushes me back toward the i7. Noise is still my only concern, but I guess the only way I can find out about that is by watching the Dell site to see if anyone who’s bought that specific laptop has written a review.

    (On the subject of RAM — I reckon the default 4Gb is going to be OK for a while, and anyway Dell charge such a ridiculous amount for upgrades that it would probably be cheaper to throw away the 2x2Gb modules and get 2 new 4Gb ones than it would be to buy 8Gb from them up front…)

    Cheers,

    Giles

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