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Thread: Jeff's Wacky Guide to building a Xeon Cruncher! (repost)

  1. #1
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    Jeff's Wacky Guide to building a Xeon Cruncher! (repost)

    Here is a repost of the 1.6GHz LV Xeon guide as requested by IronBits.

    DISCLAIMER: Only use the information posted here as a loose outline. If you attempt to do anything mentioned in this thead, you are accepting full responsibility for your actions. If you can not accept this, please do not read any further!

    Since I have been asked a few times through private messaging, I figure I will post the information for everyone to see here.


    Processor Type: Intel Xeon
    Package: 604-pin FC-PGA2/mPGA
    Stock Processor Speed: 1.60GHz
    Core Voltage: 1.3v
    Stock Multiplier: 16x (12x - 16x available)
    Bus Speed: 400MHz
    L2 Cache Size: 512Kb
    Core Stepping: D1
    sSpec: SL6XK

    eBay is the best place for low voltage processors right now. LapCompute is selling pairs for ~$100 plus $17 shipping and insurance, here is the link to his auctions:

    Addendum (April 2, 2005): These processors are now only available once in a while on eBay and through various forums with typical costs in the $150-$200 range. While this is still an decent deal... it's definitely not as good as it used to be.

    The next best thing to the D1 stepping 1.6GHz LV Xeon CPU is the C1 stepping 1.6GHz LV Xeon CPU. Note the difference in sSpec...
    D1 = SL6XK
    D1 = QQV2 (Pre-release SL6XK chips, just as good as "normal" D1s)
    C1 = SL6GV

    C1 CPUs are still a great deal at ~$100/pr since they will run 2.4GHz to 2.8GHz on average. One thing to note is I have had a few of these C1s NOT run 200MHz FSB, even after increasing core and memory voltage. A good base setting for C1 CPUs after increasing core voltage to 1.6v is 165x16=2640MHz. If you get brave and want to go for 200MHz just remember that this is not guaranteed to work.

    C1 Xeons can sometimes be found on eBay and various forums. Good luck in your LV Xeon hunt.

    The standard heat sink for Intel Xeon processors is the Intel Wind Tunnel(IWT). IWTs are great stock heatsinks and adequate for running Xeons at up to 3.2GHz. The only negative I have heard from people is in regards to noise level. Personally I am used to fan noise and actually like hearing it. (no, I am not kidding) BUT, I do admit when CPU temperatures rise, the fans can get a bit noisy. Simple solutions range from the "+7v mod" to installing a quieter fan. I think most people here have done a little "fan modding" so I will not discuss this any further. (if you need help just start a thread in the forum and someone will be glad to assist you)

    IWTs can be found on eBay for downright CHEAP. They are offered in waves with a price range of $25/pr to $40/pr delivered. $40/pr is a great price in my book so if you get lucky and get a pair for $25 then consider yourself very lucky. :up:

    Addendum (April 2, 2005): These will NOT fit NCCH-DL motherboards!

    No doubt the perfect motherboard for a cheap Xeon cruncher is the Asus PC-DL. It uses normal DDR memory and does NOT require an expensive EPS server power supply.

    eBay and are the best places to look for one. Use to find the cheapest online prices and to see who has them instock. The price has ranged from $185 to $220 over the past few months. Here is the link to start comparing...

    The Asus NCCH-DL is also a very good board for crunchers. It is ~$30 to $50 more than the PC-DL but has a few added features like seperate VRMs for each processor and an adjustable Vdimm of 2.5v to 2.8v. Core voltage is still NOT adjustable so the "u-wire" method mentioned later in this guide will also apply to the NCCH-DL. Here are a couple links to start your search for this motherboard...

    Addendum (April 2, 2005): The stock Intel Wind Tunnel heatsinks mentioned above will NOT fit the NCCH-DL motherboard!

    The Asus PC-DL does NOT require a server level power supply which is usually referred to as an EPS power supply. It can use an ATX supply with it's standard 20/4 pin power connectors or it can use a proper EPS supply which has 24/8 pin motherboard connectors instead. Personally, I like using EPS supplies for Xeon rigs but if you have a great ATX supply then why bother upgrading. Here is a picture of how the 20/4 pin connectors are attached when using an ATX power supply:

    WARNING: Most PC-DL motherboards do not have a clip to lock in an ATX's 20/4 pin power connectors. If using an ATX supply you should exercise caution when working around a live motherboard since pulling the power connectors out(or partially out) can result in damage to the system.

    Dual Xeon systems need a great deal of +12v current when overclocked so make sure your power supply has at least 20A on this rail... preferably you should get one that is capable of 25A to 30A or more if you are going to be overclocking in the 3.0GHz or higher range.

    Here are a few power supplies that should perform nicely:
    Sparkle/Fortron Source 550w EPS(single +12v rail): $101.50 + shipping
    (MONSTER power supply for the money... 36A on the +12v rail!)

    Sparkle/Fortron Source 550w EPS(single +12v rail): $89.61 + shipping
    (MONSTER power supply for the money... 36A on the +12v rail!)

    SPI/Fortron Source 550w EPS(single +12v rail): $70.00 + shipping
    (This has been sold out for months... don't know if they are ever going to carry these again. )

    OCZ 420w EPS: $86.99 + shipping
    Only buy this one for dedicated crunchers... you shouldn't have a lot of hard drives, optical drives, or a top of the line graphics card in a rig using this power supply. There has already been one OCZ 420w power supply die here at so this may not be a good one for our use. Buyer-beware!

    OCZ 520w EPS: $133.50 shipped
    (if you like having adjustable pots... get this, otherwise consider the Sparkle/Fortron Source listed above)

    AMD Mercury 460w: $55 plus shipping
    Only buy this for a dedicated cruncher since a bare-bone video card and a single hard drive is about all it is good for... other than being CHEAP!

    Like I said before you need standard DDR on the Asus PC-DL. I recommend at least PC3200 just in case you want to try and run 200MHz FSB. Currently TwinMOS PC3200 is being talked about a lot here at since most people report getting the new Winbond UTT chips. It seems more people are having luck with 256Mb sticks than 512Mb sticks. As always, your milage may vary so buyer beware.

    If you are only going to run D2OL on your Xeon monster, then you will need two 256Mb sticks of memory. With 4 instances of D2OL you will have ~100Mb-150Mb of memory free so you can still use this computer for other, basic tasks. If you are going to be using this computer daily, two 512Mb sticks of memory should be considered a minimum.

    For those wanting to take a chance with TwinMOS, here are the links:
    TwinMOS 256MB DDR PC-3200: $34 + shipping (per stick)
    TwinMOS 512MB DDR PC-3200: $55 + shipping (per stick)
    (prices as of April 2, 2005)

    (continued in next message)
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  2. #2
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    Any AGP or PCI graphics card will be fine. You can decide on your own what you need. Personally I have only been using 9200 Radeon class cards or less. I am a farmer... not a gamer.

    Addendum (March 11, 2005): forum member shmaa has had great luck buying basic video cards from for ~$10 each. As of this writing, they have some great deals on $5 and $9 cards. :up:

    Here is a word of caution by shmaa of
    Jeff, It was brought to my attention that that Number 9 S3 card I posted about in the other thread is a 2X AGP... so it WILL NOT work in an Intel chipset systems... please add something about doing some research when buying from dumpinggoods as to what AGP spec the cheapo cards are... you need at least a 4X card for Intel systems. Those cards should be OK in an AMD system, however.
    1.0Gb is the minimum needed for Windows 2000.
    2.5Gb is the minimum needed for WinXP (no SP).
    4.0Gb is adequate for WinXP SP2 and all D2OL programs.

    But again, you know what you need here.

    Once you get everything needed. STOP!!! You have to do a few things to the motherboard to help it keep itself cool and to get the most out of your Xeons.

    First thing you will want to do once you take your Asus PC-DL out of it's anti-static bag is remove the VRM heatsink and the chipset heatsink.

    The VRM heatsink is silver in color and uses a thermal compound that honestly looks and feels like bubble gum. :down:

    The chipset heatsink is black and, thank God, uses a little better thermal compound. The problem is on 4 out of my 5 motherboards it is not making adequate contact.

    Addendum (January 29, 2005): Since first starting to write this guide I have received 3 more PC-DLs and all of these have had great chipset heatsink contact. I would now recommend NOT removing this heatsink since there probably will be no gains made in doing so. BUT, if you are having problems with unstability at higher FSB, you may want to consider it.

    NOTE: Since the thermal compound used for the chipset heatsink can be difficult to clean, only experienced people should attempt this "re-paste". Unless you are going to run very high bus rates, the stock compound is probably good enough for most users.

    Use Ceramique by Arctic Silver or your favorite paste on both after you thoroughly clean the original compounds off. MAKE SURE TO USE NON-CONDUCTIVE PASTE OR YOU COULD DAMAGE YOUR MOTHERBOARD AND/OR PROCESSORS!!! A small amount of Goo-Gone will be helpful when removing the old chipset compound. Very simple things to do and the pay off is big in the long run. (both VRM and chipset over-heating will cause instabilities when running 24/7 full-load)

    Another recommended thing to do is to add a small heatsink to the voltage regulators(VR) inbetween the chipset and the AGP port.

    The temperature of these VRs has been measure to ~90c when running a overclocked rig at full-load and no air flow. I can not stress how important air flow over this entire area is. You should have a fan blowing across the VRs, the chipset heatsink, and the VRM heatsink at all times. And you do not have to have a super high flow fan either, just use a fan that moves air.

    Next on the list of things to do is a little Vcore boost. The easiest way to do this is called the "U-wire" method. Basically you take some extremely small gauge wire and u-wire pins of the CPU together. Doing this in the socket is very easy and what I'll describe here. (you can use one strand of twisted speaker wire or twisted electrical cord wire for u-wiring)

    In order to increase these Xeons from their stock 1.3v Vcore to a more respectable and managable Vcore, we need to add a couple/three u-wires PER CPU.

    WARNING: The following information is for LOW VOLTAGE(1.3v) Xeons Only!!! Do not follow these u-wire suggestions if you have a different processor.

    For 1.5v(which will result ~1.45v on the PC-DL):

    Pins B2-B3 need a u-wire.
    Pins C2-C3 need a u-wire.

    For 1.6v(which will result in 1.55v on the PC-DL):

    Pins B2-B3 need a u-wire.
    Pins C2-C3 need a u-wire.
    Pins D2-D3 need a u-wire.

    Again, this needs to be done on BOTH CPUs.
    (notice in both pictures this is CPU1 and the orientation of the latch lever up top, use these for reference to make sure you are placing your u-wires in the correct locations)

    I suggest placing the u-wires for CPU1 first, installing a Xeon in that socket, then moving on to CPU2. The Xeons will resist going into the socket a little but should still basically just go right in. If you have to press hard... the gauge of the wire is too big or you may have a stray slightly bent pin somewhere. STOP TRYING TO FORCE THE XEON IN THE SOCKET!!! Take a step back and examine your u-wire job and the pins on the Xeon. Correct whatever needs correcting and try again. PLEASE TAKE YOUR TIME!!! I would really hate having someone break their Xeon or PC-DL.

    Ok, once you have both Xeons in their sockets you need to install the Intel Wind Tunnels. The directions included with these heatsinks are very good and explain all the steps needed to successfully install them. If you have any questions or problems with this step just post a message on the forums and someone will give you a hand.

    WARNING: So far two people have experienced problems when there is a Xeon in the CPU2 socket. Both incidents have been traced back to a shorted trace between the motherboard and the metal plate that holds the IWT to the motherboard. Nylon washers should be used on at least CPU2 because of this potential problem. No damage has occured so far because of this shorted trace... but I highly recommend NOT taking a chance here. For a little more information, please see the following thread:

    One of the biggest downfalls to the Asus PC-DL is the lack of memory voltage(Vddr) control. The stock motherboard only provides 2.45v to 2.50v and while this may be decent enough for some memory at loose timings to run DDR400 speeds... it is not enough for most memory at default timings.

    The Vddr modification should be considered optional. The PC-DL can run with memory dividers so even if you choose to run 200MHz FSB your memory can still run at 166MHz or 133MHz. The biggest reason I am calling this optional though is that it requires the soldering of wires. If you are not comfortable with soldering do NOT experiment with your $200 motherboard. Either live with running a divider or find a friend or relative who can solder for you. Do not kill your $200 motherboard!

    This mod is about as easy as it comes for Vddr mods. You need to put a 10K Ohm variable resistor between pin 6 and ground of the control chip(sorry... I can not read the markings on this ).

    You can choose whatever ground you like. I prefer to use either the ground of a fan header or a screw hole. The advantage to the fan header is that you can disable the mod by just removing this wire. But either place(or other places) will do.

    Addendum (February 4, 2005): There is a little easier alternative to the Vddr mod. that uses the middle pad near the coil pictured below instead of Pin6 of the controller. These two points are electrically equivilent so feel free to use whichever is easier for you.

    BTW, the other solder point shown above is a ground. You can use that or any other ground.

    Before you solder the VR in place, make sure to set it to at least 5K Ohm. At 5K Ohm PC-DL motherboards will run between 2.8v and 3.0v to the memory. The lower you turn the resistance the higher the voltage will go. YOU NEED A DIGITAL MULTIMETER TO READ Vddr! In the above picture you will notice the place to measure Vddr. There is no software tool that can read this voltage. Use caution when measuring Vddr so you do not short another component. Doing so can and most likely will damage your motherboard/CPUs/memory/etc.

    A word about Vddr... Here is my $0.02... or £0.0107 for those across the pond... 3.0v and up is fine to run with older BH-5, BH-6, CH-5, and the newer TwinMOS RAM. I have next to NO EXPERIENCE with other type ram so 3.0v may be a bit too much for them. Please use common sense with this voltage and start out with the VR at 10K Ohm and work your way down from there keeping an eye on Vddr. Personally, I do not see a problem wiring a 5K Ohm resistor(not a variable resistor) here and calling it good. The memory I mention above loves voltage and the PC-DL does not seem to have a problem supplying up to 3.5v(people over at have run this high... personally I have never been over 3.2v on a PC-DL). Again, use common sense and try not to damage your $200 motherboard.

    (continued in next message)
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  3. #3
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    Now it's time to install everything else that you normally install with a new computer. The PC-DL is a standard ATX motherboard so most any case will do. Just be sure to have adequate air flow throughout and you should not have any problems.

    Time for your first boot. :up: When you turn your new rig on for the first time it should boot at 16x100=1.6GHz. While this is nice... it's just not going to do. First thing you are going to want to do is make sure both processors are showing up and that your memory is showing up in the correct quantity and that it passes the BIOS test.

    And after it does, turn off the machine and it is time to do a little Jumper Shuffle. This following configuration is how all PC-DL motherboards are shipped from the factor...

    This is the "auto" setting for FSB and will never again be used.

    In order to boot at 133MHz, you need to change the jumpers to this...

    This setting will give you the option of booting at between 133MHz and 165MHz. Some people may actually be happy here, but as long as you bought the D1 stepping Xeons I told you to buy, you can go a lot further.

    Assuming you did, you will now want to go into the BIOS and change your multiplier to 15x. You will also want to make sure the FSB is at 133MHz and the memory setting is at 133MHz. Timings are up to you and your memory. If you are running BH-5, BH-6, CH-5, or the new TwinMOS I mentioned above then you should choose "2-2-2-5" right from the start.

    And also feel free to change all your other BIOS setting now too. If you want to turn off the boot screen, or get rid of SATA, or whatever... feel free to do it now(but do NOT change away from the setting I mentioned above).

    After you happy with the BIOS, save the configuration and reboot. Once you see the boot screen again and your the memory test completes, shut down your computer.

    It is time for 200MHz FSB. Change the jumper one last time to this...

    Now reboot. If everything works like it should, you should boot at 15x200=3.0GHz. If it does not, move the jumper back to it's 133MHz setting, go back into the BIOS, change your multiplier to 14x, and try again. If this doesn't work either, move the jumper back to it's 133MHz setting, go back into the BIOS, change your memory settings to "auto", and try again. If this doesn't work, take a break... come back fresh... and check your work again. If nothing looks wrong and you still are not having any luck, post on the forum and someone will help you out ASAP.

    To keep track of your speeds, temperatures, and memory in Windows, there are a few utilities you will want to download.

    CPU-Z: Tracks overall cpu MHz and memory speeds/settings.

    ClockGen: Adjust cpu MHz and memory speed in Windows.
    (The Asus PC-DL uses version CG-ICS952618)

    Tweak 865/875/848: Adjust memory parameters in Windows.

    Motherboard Monitor: Monitor temperatures and voltages.

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