Alphacool NexXxos XP water block

Cooling/Water Cooling by KeithSuppe @ 2004-11-12

We?re rapidly approaching the point where these HSF (Heat Sink Fan) combinations are simply too large and heavy to mount on our motherboards. Given the benefits of H20, it?s only a matter of time until most CPU?s are water-cooled. We take a closer look at Alphacool?s NexXxos XP water block. Can it keep an overclocked Prescott running cool at 4Ghz? Read on to find out

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System and Test Setup

Our test setup features an Asus P4C800E-Deluxe motherboard in combination with Intel's first foray into the 09-micron core for S478, the Prescott 3.0E. I chose the Socket 478 Prescott specifically for its notoriously high heat (wattage) output. If the NexXxos XP can cool a CPU running hot enough to double as a Space Heater, then its reputation, and place on the Euro charts is well deserved

Additionally we'll overclock our already hot running Prescott, challenging the NexXxos XP even more. There are several programs which generate heat, and I chose to use Prime95.

To measure the temperature, I'll use two methods:
  • Intel internal thermal diode monitoring via Asus’ PC Probe
  • Placing a thermistor directly between the CPU and water block, read by TTGI/SuperFlower’s SF-609 (rheostat/temp monitor).

    System configuration:

    Liquid3D's Test Setup
    CPU Intel P4 3.0 “E” Prescott SL79L Philippines
    Mainboard Asus P4C800-E Deluxe (Bios rev 1018)
    Memory Corsair PC3200 TwinX 1024 XL Pro
    Other Components Video: - eVGA 6800 GT (256MB, nForce 61.77)
    Power Supply: PCPower&Cooling TurboCool 510 Deluxe
    Cooling: Alphacool Xtreme Pro Set, NexXxos XP, AP1500 (900l/h @ 12V 1500l/h @ 24V), Black Ice Xtreme II, 2x120mm Sunon's 95CFM, Coolplex 25 reservoir, 1/4" line

    Test configuration:

    Installing the NexXxos XP block itself was simple, and took no more then a few moments. Using the retention clamp for S478, all one need do is insert the clamp, center the bars, and tighten. I ran the system with the radiator, and Coolplex reservoir outside of the case, which has its side-panel removed. This not only aids in cooling, but eliminates any discrepancy between the room/ambient temp, and case/MB temp. The photo below shows my setup to get a clear idea of where it's situated. When overclocking I will open the window near the PC, however; due to the fact a sudden breeze or change in outside temp may cause temperatures to fluctuate by more then a few degrees, I always close the window while testing.

    Madshrimps (c)

    As I stated above the block installs easily, tightening the center bolt backs out the hardware against the Socket 478's retention bracket. Once adjusted so the clamps are evenly inserted into the plastic retention mount, an impression in the block's top-plate guides the screw. The wire in the photo below is from the thermistor inserted between CPU and water block. I remount the water block in every review at least 4-times, until the highest temp is indicated on the SF-609. It's almost impossible to place a thermistor so it's reaching the center of the CPU without adversely affecting contact between water block and CPU. To circumvent this you can Dremel copper from the base plate, or from your CPU's IHS matching an impression of the thermistor and wire. Since any heatsink or water block must make 100% surface contact with the CPU in order for thermal transfer to safely occur, removing an amount of material matching that of the thermistor may be the best method. In this case I compared, and extrapolated temps from several sources including Intel's internal thermal diode. I've found the location of this sensor to be dangerously low in the Northwood, however due to the heat output of their .09-micron core I believe Intel may have found a much more suitable (accurate) location for their “readable” internal thermal diode.

    Madshrimps (c)

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