This content was originally featured on Amdmb.com and has been converted to PC Perspective’s website. Some color changes and flaws may appear.I tested the HydroCool 200 system on the same AMD Athlon XP-2400+ platform I use for all heatsink and waterblock evaluations. This computer is an open chassis rig running at stock speeds and voltages.
Test computer components:
- Epox 8RDA+ nForce2 motherboard with 3129 BIOS
- AMD Thoroughbred XP-2400+ @ 2000 MHz and 1.65 Vcore
- Ambient air – Barnant Model 115 digital thermometer (accuracy +/- 0.4º C)
- CPU – Barnant Model 115 digital thermometer (accuracy +/- 0.4º C)
- Water temperature – measured in reservoir with digital lab thermometer
- Calibration – ASTM-T mercury precision thermometer (accuracy +/- 0.1º C)
- Extech Model 407736 digital sound level meter (accuracy +/- 1.5 dB)
The CPU was fully loaded by running the distributed computing application Folding@Home. Before each mounting, both the CPU and waterblock base were cleaned with isopropyl alcohol and a very thin coat of AS3 was applied to the CPU core.
I used both the motherboard in-socket thermistor and a calibrated thermocouple attached to the CPU to record temperatures. I have found from previous testing on this board that the in-socket thermistor reliably reads about 10 degrees lower than the calibrated thermocouple attached to the bottom of the CPU. It also corresponds within a degree or two with ambient at startup (from BIOS), which gives a good indication it is providing a relatively accurate reading.
The following data is presented for comparative purposes only. Your actual results may be different depending on the variables unique to your system (CPU, overclock, ambient temperature, case air flow, temperature monitoring, etc).
The following graph shows the HydroCool 200 system CPU temperatures as reported by the EPoX in-socket thermistor as they are consistent with what most people are familiar with. The standard Athlon OEM heatsink fan is included for comparison.
Click to Enlarge
As you can see, the HydroCool 200 system performed remarkably well – far better than I had initially expected! From the data we can draw several conclusions.
- Obviously the Delphi engineers have optimized the system for low flow rates. I believe the small, micro-channel waterblock is the key. Yes, there are other waterblocks available that offer even better performance for the hard-core overclocker but the HydroCool block is designed to work efficiently with a mere 27 GPH flow rate. The rest of the system can then be designed to support the needs of this waterblock.
- Because the overall system flow rate (GPH) is so low the water velocity (FPS) moving thru all the components is also very low. The smaller the internal diameter of components and tubing, the higher the water velocity will be per a given flow rate. Again, because the system flow rate is so low, components can be made quite small (tubing, fittings, etc.) while at the same time keeping the water velocity low.
Flow resistance is directly proportional to water velocity (not flow rate). Many of the components we earlier identified as potential flow killers (elbow fittings, quick-disconnects with internal check valves, flow indicator, 1/4” ID tubing) will have less impact on system flow if the velocity of the water flowing thru them is low.
- The systems heat rejection performance (radiator/fan) works quite well for a compact, relatively quiet system. The average water temperature was typically 2.5ºC to 3.5ºC above the ambient air temperature.
- The difference between Whisper and Turbo mode (slow and high fan speed) resulted in only a degree or less in cooling performance.