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Shuttle is true to itself and we still see one cooling device and a half in the XPC: CPU and general-system ICE cooler and a Silent X power supply unit.
Silent X is a recent series of power supply units in Shuttle, which is notable for increased capacity and improved cooling at a moderate noise level. It should be noted that 250 W is far from a record these days (for example, Soltek uses 300 W power supply units), but we had no problems with it in our tests, though we imitated the maximum possible system load (3D games + copying data from DVD). The power supply unit has a fan at each face, which provides better air flow though its innards as well as improves cooling of the front area of the barebone. The fans used are from respectable Delta (EFB0412MD: 40x40x20 mm, 7.17 CFM, 24 dBA), very quiet, with automatic rpm control. As the northbridge of the chipset and field-effect transistors in the power supply circuit of the processor are covered only with heatsinks, there are no other noise sources in the system. The power supply unit has two SATA power connectors. What concerns a floppy drive, you'll have to use a bundled power converter, because the modern power supply unit has no such connector.
Shuttle SB77G5 uses the ICE system for a CPU cooler of a new modification, a traditional solution for all barebones from this company. It has the same operating principle: a heatsink with an embedded copper plate at the base channels the heat from CPU via heat pipes to the upper heatsink, which is mounted at the grill on the rear panel. The upper heatsink is equipped with a powerful fan, which draws out hot air from the case and blows through the plate fins of this heatsink. The new ICE modification has a CPU heatsink of an unusual appearance (a la titanium) – according to Shuttle, its thermal resistance is reduced nearly twofold relative to the earlier ICE models) – and an enlarged fan, it's now 92 mm (Shuttle DA09225R12U). This solution looks very good, because the previously used 80 mm fan from Sunon was very noisy, though it offered excellent performance. (As a result, well-to-do Shuttle XPC buyers even used to order special fans with reduced noise level at the same or higher capacity from third-party companies.)
The maximum fan speed is ~3800 rpm, but as in all other Shuttle XPC models, the SB77G5 BIOS incorporates an automatic rpm control technology – Smart Fan. You can choose one of three operating modes: always maximum rpm (you can control it later with Windows utilities – but SpeedFan did not cope with it); speed it up it to maximum at 75°C, but keep it at ~900 rpm on other cases (Ultra-Low mode), ~1550 rpm (Low mode) or ~2250 rpm (Mid mode); or Smart Fan. In the last, the most interesting and frequently used case, the rotational speed changes automatically stepwise: before the critical temperature specified in BIOS is reached (within 25–75°C) the rpm is minimal (~950 rpm), but each degree above the critical limit increases the rpm in the specified manner (by 100-200 rpm). The system possesses enough sluggishness not to change rpm constantly (±1°C in cycle). Besides, the audible differences between the neighbouring modes are minimal.
We have carried out all the tests in Smart Fan mode, the temperature threshold was set by default to 60°C. The system was assembled to maximum: Pentium 4 Extreme Edition 3.4 GHz, ATI Radeon 9800XT, sound card, 7200 rpm HDD, DVD drive, floppy drive. The temperature in idle mode was measured in 20 minutes of idleness after Windows startup, the full load mode was provided by FarCry at high resolution together with Folding@Home client calculations. We decided that DVD recording added to the task list would be too artificial.
Inconsiderable temperature difference between polar modes illustrates well the work of Smart Fan: if the temperature is within admissible limits, the noise level should be reduced instead of the temperature. Though all old Intel processors cannot reduce their clock/voltage in idle mode (see our articles in the CPU section) unlike their modern successors or AMD Athlon 64/FX, Smart Fan functions should satisfy PC users. An improved ICE cooler together with well thought-out cooling solution (Smart Fan) have led to Shuttle SB77G5 being one of the best models on the market by its subjective noise level. It noticeably outscores both the older XPC models as well as the competing products (before this review we named Soltek Qbic with its IcyQ cooling system to be the model). The praise is deserved not by characteristics in some certain conditions but by the constant optimal thermal conditions at minimum necessary fan activities and correspondingly minimum noise. Note that the ICE fan does not have to rotate faster than ~1600 rpm, so the maximum cooler modes in BIOS are somewhat surprising.
Sergei Pikalov (firstname.lastname@example.org)|
February 28, 2005