Dell Precision 690


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Dell Precision 690

  • Hello All.
    I have recentely aquired a 690 1000w unit and notice the memory risers cards inside. If i'm only using 4 gigs of memory to begin with is it recommended that the risers be removed?
    If not is it recommended that a stick of 1 gig or ram be put onto each riser?
    Thanks for looking.
  • Titon4,

    Welcome to the Dell Community Forums.

    It would depend on what you are planning to do with the system. If you are going to in the future upgrade to a 64 bit operating system, then you would want to leave the risers in place.

    If not, then it would be your choice to remove them or not. Memory put on the riser does have to have the heat shield on them for heat dissipation, and has to be put in matched pairs like memory not on the risers.

    Message Edited by DELL-Elsbeth on 10-22-2007 08:16 AM
  • Thanks for the welcome!
    Well i plan on installing a new HD and going with either XP64 or Vista64. Explain to me matched pairs and how you would put them on the risers? Do i have to put a pair on *each* section of the risers?
    Plus i'm upgrading to Quad core processors. In some instances it looks like people do not attach the fans to the heat sinks. My new processors come with both. I do install the fans correct?
    Thanks for the info!
  • Titon4,

    All DIMMs need to be heat shielded and fully buffered.

    There are 8 memory slots on the system board. The slots are numbered DIMM1 through DIMM8. DIMM1 is closest to the PCI slots and it is numbered through DIMM8 towards the outside of the system board.

    To achieve full bandwidth operation, memory configurations should consist of sets of four identically matched DIMMs to allow Quad-Channel operation. The sets of DIMMs must be identical with respect to capacity, rank, and organization (x4 or x8). Speed and CAS latency do not necessarily need to match, but the slowest speed DIMM and highest CAS latency will set the operating mode of the system.

    Configurations of four matched DIMMs must use DIMM1, DIMM2, DIMM3, and DIMM4 slots. These configurations allow full bandwidth.

    Eight DIMM configurations use all eight DIMM slots and must consist of two matched sets of four DIMMs. These configurations have the same full bandwidth as four DIMM configurations.

    The memory expansion risers (RISER_1, 2, 3, and 4) plug directly into the memory slots on the system board (DIMM_1, 2, 3, and 4 respectively). They increase the available memory slots from eight to sixteen. The memory expansion risers are not interchangeable, and each will only work with its correspondingly numbered slot. They come assembled in pairs with RISER_1 and RISER_2 fastened together, and RISER_3 and RISER_4 together.

    There are four unique memory risers that must be installed together into motherboard DIMM_1, DIMM_2, DIMM_3, DIMM_4 slots. (RISER_1 plugs into DIMM_1 slot, RISER_2 into DIMM_2, etc)
    When risers are installed, nothing may be installed in motherboard slots DIMM_5 - DIMM_8
    Each of the four risers provides four DIMM slots, resulting in a total of sixteen slots available
    Configurations of four matched DIMMs need to be installed one per riser starting with the lower-most riser slot (labeled DIMM_1):

    For example, a set of four matched would be installed in RISER_1-DIMM_1, RISER_2-DIMM_1, RISER_3-DIMM_1, and RISER_4-DIMM_1.
    All four risers must be spanned with the matched set of DIMMs in order to achieve full bandwidth operation.
    Each riser corresponds to a single FBD channel.
    Configurations of eight, twelve and sixteen DIMMs must be composed of sets of four matched DIMMs, installed with one DIMM of each set on each riser. This maintains the required spanning to get full four-channel bandwidth.

    As far as the processor, it would be best to install the heat sink and fan together.

    Message Edited by DELL-Elsbeth on 10-23-2007 07:10 AM
  • Thanks again for the reply. That answers a lot of questions.
    Now another. I just started assembling the processors into the system. Unfortunately i cannot find a power connector on the dell board for the processor fans? Is this normal or do i have to come up with some way to power the fans from the supply?
  • Titon4,

    There should be a connector from the power supply for the fans. I do not see any connector on the system board for processor fans.
  • Thanks again for the reply.
    Unfortunately i've been up and down the wires from the power supply and do not see any connectors for the processor fans. I would imagine that i'd have to connect them some how to the power supply yet the fan's have 4 pin female connectors and everything i see on the net has 3 to 4 pin adapters.
    I'm at a loss as to what to do with this.
    There is no connection for cpu fans anywhere on the motherboard. I realize that this is rigged for passive cooling but wish to use the fan's anyways. The new Xeon's i purchased have a 4 pin female connector on them instead of a standard 3 pin that i've always seen. For the life of me i cannot find a convertor anywhere that will plug into the cpu 4 pin fan connector and go to the standard molex style connector from the power supply. What the heck am i missing here?

    Message Edited by Titon4 on 10-24-2007 07:53 AM
  • you cannot find the adapter you want because (for the most part) no one makes its. It is pointless as the 4th wire is for speed control so even if the adapter was made, the fourth Pin/wire would still be doing nothing. Same as if you just plug the 4-pin fan into a 3-pin (mobo connector or 3-pin fan to 4-pin molex connector. 
  • Thanks for the responses!
    I ordered heatsinks to take care of the problem.
  • Titon4

    I upgraded to windows 7 64 bit - removed the risers, took each matched pair of memory sticks and divided them between dim slot 1&2 and dim slot 4&5 this put 2 gig of the original memory on each CPU. I then purchased two (2) sets of 2 X 2 and put them in the remaining slots 3&4 and 7&8 this gave me 12 Gig on the motherboard - I turfed the risers. These days you can (if you can afford it) go up to the 64 gig limit right on the motherboard with (2 x 8) x 8. Have fun. oh yes if you do load her up be prepared to install a thermal electric cooler.