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Thread: Intel Core i5 2500K Linux Performance

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  1. #1
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    Default Intel Core i5 2500K Linux Performance

    Phoronix: Intel Core i5 2500K Linux Performance

    Earlier this month Intel released their first "Sandy Bridge" processors to much excitement. However, for Linux users seeking to utilize the next-generation Intel HD graphics found on these new CPUs, it meant problems. Up to this point we have largely been looking at the graphics side of Sandy Bridge, and while we have yet to publish any results there due to some isolated issues, on the CPU side its Linux experience and performance has been nothing short of incredible. Here are the first Linux benchmarks of the Intel Core i5 2500K processor.

    http://www.phoronix.com/vr.php?view=15648

  2. #2
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    Default Note about difference between 2500 and 2500K

    At the page nine of the article Intel Core i5 2500K Linux Performance it's said

    There is also the Core i5 2500 non-K processor that retails for about $10 less than the K version, with the sole difference being the 2500K being an unlocked processor so it will be able to overclock better. If doing any overclocking, you are best off with the K variant.
    This is a false statement and should be corrected ASAP, as the untrue info potentially affects many Linux users. The K version is better for overclocking, but it has some features crippled compared to the non-K version. It lacks trusted execution and VT-d support. See the product details of the 2500 and 2500K, the Advanced Technologies table.

    Especially the latter might be a deal-breaker. VT-d support allows a host machine to share physical PCI devices to guest hosts when running KVM based virtualization systems. With the new Sandy Bridge K processors you can't do that. Many people might want to experiment with this features as it's supported by modern Linux distributions. But you need the non-K processor for that.

    I guess Intel is crippling the overclockable processor because those interested in overclocking probably aren't interested in enterprise features (though people at this forum might make an exception to this assumption). This way they also prevent cheap-ass people from building servers with "too good" power/performance/price ratio using the over clocked K processors thus leaving room for their upcoming Sandy Bridge Xeons...

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    Quote Originally Posted by tjormola View Post
    At the page nine of the article Intel Core i5 2500K Linux Performance it's said



    This is a false statement and should be corrected ASAP, as the untrue info potentially affects many Linux users. The K version is better for overclocking, but it has some features crippled compared to the non-K version. It lacks trusted execution and VT-d support. See the product details of the 2500 and 2500K, the Advanced Technologies table.

    Especially the latter might be a deal-breaker. VT-d support allows a host machine to share physical PCI devices to guest hosts when running KVM based virtualization systems. With the new Sandy Bridge K processors you can't do that. Many people might want to experiment with this features as it's supported by modern Linux distributions. But you need the non-K processor for that.

    I guess Intel is crippling the overclockable processor because those interested in overclocking probably aren't interested in enterprise features (though people at this forum might make an exception to this assumption). This way they also prevent cheap-ass people from building servers with "too good" power/performance/price ratio using the over clocked K processors thus leaving room for their upcoming Sandy Bridge Xeons...
    Thanks for this information, much appreciated. Intel's market segmentation is getting worse. For me, no VT-d and/or locked clocks == no sell. AMD may lack raw speed at the high end, but if I buy a Phenom I rest assured that I'll get both VT and overclocking potential.

    Quote Originally Posted by Lukian
    Nice cut on your finger. Sharp motherboard / case?
    (Happens far too often.)
    If you don't shed blood over your new computer, it won't work. It's been proven time and time again.

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    Quote Originally Posted by BlackStar View Post
    Thanks for this information, much appreciated. Intel's market segmentation is getting worse. For me, no VT-d and/or locked clocks == no sell. AMD may lack raw speed at the high end, but if I buy a Phenom I rest assured that I'll get both VT and overclocking potential.
    Do not confuse Vt-d and Vt-x. Vt-x means general hardware virtualization support, and all Sandy Bridge CPUs available today support it. Vt-d means virtualization support for I/O devices direct access - simmilar to AMDs IOMMU nowadays available only on 890FX chipset. Even not all manufacturers support IOMMU correctly in their crappy BIOSes. Same as Intel Vt-d motherboard support.

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    Quote Originally Posted by next9 View Post
    Do not confuse Vt-d and Vt-x. Vt-x means general hardware virtualization support, and all Sandy Bridge CPUs available today support it. Vt-d means virtualization support for I/O devices direct access - simmilar to AMDs IOMMU nowadays available only on 890FX chipset. Even not all manufacturers support IOMMU correctly in their crappy BIOSes. Same as Intel Vt-d motherboard support.
    Ah, that's better.

  6. #6
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    Default No VT-d does not equal no VT

    Quote Originally Posted by BlackStar View Post
    Thanks for this information, much appreciated. Intel's market segmentation is getting worse. For me, no VT-d and/or locked clocks == no sell. AMD may lack raw speed at the high end, but if I buy a Phenom I rest assured that I'll get both VT and overclocking potential.



    If you don't shed blood over your new computer, it won't work. It's been proven time and time again.
    You are thinking that no VT-d = no VT at all.

    Every second-generation i-series, and without exception, supports VT-x. Not ten percent (the K-subseries), but every second-gen i7, i5, and even i3. VT-d is a *superset* of VT which includes virtualization of I/O. While KVM-based virtualization software (and most desktop virtualization software nowadays) supports VT-d, it also, by and large, still supports old-school VT-x.

    The difference between VT-d and VT-x, from the OS/application point of view (which is the true determinant of which is more suitable) is that VT-d includes virtualized I/O (such as SATA, USB, et. alia), while VT-x makes do with plain old *emulated* I/O. Intel had made VT-x practically standard in most LGA775 CPUs (when they replaced E1xxx with E3xxx, the newer series supports VT-x, while the older CPUs did not) - only the Pentium Dual-Core and some C2Ds and early C2Qs lacked VT-x.

    One important tack taken with LGA1366 and the followups - with few exceptions, they all support VT-x. In short, hardware virtualization has become a check-box item, at least on the Intel side of things.

  7. #7
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    Unhappy Not very stable around here...

    (from the article): The new Intel chipsets required for Sandy Bridge support, which right now are the H67 and P67, are also playing well with modern Linux distributions.
    Hmm, I've just upgraded one of my CentOS 5.5 systems with a Core i7 2600 + Intel DH67CL motherboard (with H67 chipset). Due to the problems with the integrated graphics mentioned in the last Sandy Bridge Phoronix article, I moved over the old and reliable Geforce 7xxx PCI-e 16x graphics card from the old system and disabled the integrated graphics permanently in the BIOS.

    The system got exactly a few seconds past GRUB and then it crashed. I further disabled all the fancy stuff; USB3, onboard audio, SATA 3.0, etc. and after a few tries the system booted X11 and then it crashed after 20-30 seconds.

    I still have several things to test in order to draw any conclusions, but it's not looking good so far

    New BIOS, memtest86 and test of a newer Linux distribution is up next.

  8. #8
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    Excuse me... how do you run Linux with Sandy Bridge? Does that motherboard have UEFI BIOS? If so, how does the CentOS system, which is effectively RedHat Linux, run off that motherboard - as far a I know, UEFI implies GPT, and GPT implies GRUB 2, which RedHat is not going to use in the near future. How do you use GPT and GRUB 1, if it is GPT and UEFI?

  9. #9
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    Quote Originally Posted by Kenni View Post
    Hmm, I've just upgraded one of my CentOS 5.5 systems with a Core i7 2600 + Intel DH67CL motherboard (with H67 chipset).
    That's the same motherboard that I have here and I had no problems booting an old Centos 5 install on it. I did have a newer kernel than Centos supplies - I think mine was 2.6.32.5 and is now 2.6.36.2. I'd check it with memtest86+ first (and you need the beta version of that too).

  10. #10
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    Smile

    Quote Originally Posted by Kenni View Post
    Hmm, I've just upgraded one of my CentOS 5.5 systems with a Core i7 2600 + Intel DH67CL motherboard (with H67 chipset). Due to the problems with the integrated graphics mentioned in the last Sandy Bridge Phoronix article, I moved over the old and reliable Geforce 7xxx PCI-e 16x graphics card from the old system and disabled the integrated graphics permanently in the BIOS.

    The system got exactly a few seconds past GRUB and then it crashed. I further disabled all the fancy stuff; USB3, onboard audio, SATA 3.0, etc. and after a few tries the system booted X11 and then it crashed after 20-30 seconds.

    I still have several things to test in order to draw any conclusions, but it's not looking good so far

    New BIOS, memtest86 and test of a newer Linux distribution is up next.
    I finally identified the issue, the onboard SATA 3.0 has issues. Once I moved the HDDs to the SATA 2.0 controller, the system got rock stable.

    It didn't matter if I ran Ubuntu 10.10, Ubuntu 11.04 Alpha1 or CentOS (with kernel 2.6.18 or 2.6.37), they all crashed eventually.

    I don't know if it's a local HW problem on my board, but if your Sandy Bridge Intel board is unstable, try to skip the SATA 3.0 ports to see if it helps.

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