Here is the mainboard used in Shuttle SB51G barebone system:

The mainboard used in Shuttle SB51G is Shuttle’s own FB51 solution. Although it is of pretty small size, it nevertheless, feature the entire set of advantages typical of the full-size ATX mainboards. FB51 is built on a pretty modern i845GE chipset and supports Socket478 processors with 400MHz and 533MHz FSB, as well as Hyper-Threading technology. There are two DDR DIMM slots on the mainboard, which support DDR266/DDR333 SDRAM. As for the extension capabilities, the mainboard is equipped with an AGP 4x and one PCI slot. In fact, these slots should be quite enough, especially keeping in mind that there are a lot of onboard controllers integrated onto the PCB.

Due to ICH4 South Bridge, the mainboard supports 6 USB 2.0 ports (as we have already said, two of them are located on the front and two on the back panel of the cube, while the remaining two slots haven’t been laid out). Three additional IEEE1394 ports have been implemented via the VT6306 controller from VIA; 6-channel AC’97 sound is provided by Avance Logic ALC650 codec and 10/100Mbit Ethernet support is ensured by the Realtek RTL8100B controller.

Since Shuttle SB51G is intended for advanced users, the BIOS Setup of FB51 mainboard boasts some overclocking-friendly functions. In particular the mainboard allows adjusting the FSB frequency within the range starting with 100MHz and ending with 165MHz with 1MHz increment. Unfortunately, there are no other options available like the opportunity to change the processor Vcore or AGP/PCI bus frequency. But we should be happy with what we’ve got. The traditional barebone systems have never had any overclocking-friendly functions at all.

The small form-factor system from Shuttle required a special power supply unit. The engineers decided on a 200W PSU from the Taiwanese Achme company, which appeared considerably smaller than the regular PSUs. 200W of power generated by this unit should be more than enough for the CPU, add-on graphics card, hard disk drive, optical drive, mainboard with the memory and a few USB devices. This power supply unit worked very well. Its only disadvantage appeared very high heat dissipation under heavy workload. As fore the power supply connectors of this unit, there are 5 additional “tails”, which serve to power not only the HDD, optical drive and a floppy, but also the second HDD or an add-on graphics card requiring extra power supply.

Shuttle engineers paid a lot of attention to the cooling solution used in their barebone cube. The company engineers tried to make sure that the cooling solution used is not only efficient from the thermal point of view, but also produces not too much noise. Therefore, Shuttle SB51G is equipped with just a pair of fans. One of them is situated inside the power supply unit and is probably intended to cool down the insides of the PSU in the first place. The second 80mm fan is placed on the case rear panel and blows the warm air outside the case. Its rotation speed depends on the processor temperature and equals 2500rpm in regular working conditions. Moreover, the same fan sends the air stream through the heatsink, which receives the heat from the CPU via the special heatpipes. Despite the seeming bulkiness of this cooling solution, it proved quite efficient.

As for the system design, we should give due credit to Shuttle engineers for the great job they did. You will easily fit even a full-size graphics card, like GeForce4 Ti4600, into this case. However, since the AGP slot is located very closely pressed to the case side, you will be unable to use graphics cards with large cooling solutions onboard, such as GeForce FX or ABIT solutions with OTES cooling system. Due to the fact that there is no CPU heatsink, and the heat is transferred to the remote heatsink via the heatpipes, there is quite enough room inside the case, even though it is of relatively small size. This ensures proper air circulation inside the case cooling down the other system components. It looks as if the only thing that can upset you during the Shuttle SB51G system assembly is the necessity to place some cables in a not very common and easy way. Besides, we were a little surprised to discover no round cables inside, which we consider to be very helpful and efficient in a system like that.