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Shuttle's XPC ST20G5 mini-barebones system


Manufacturer Shuttle
Model XPC ST20G5
Price (MSRP) $350
Availability Soon

ALTHOUGH ATHLON 64 processors undoubtedly deliver an attractive price/performance ratio, the platform's lack of a competent integrated graphics chipset makes it less appealing for budget and business systems. That changed with the introduction of ATI's Radeon Xpress 200 chipset, which boasts a DirectX 9 integrated graphics processor (IGP) derived from the company's successful R300 architecture. The Radeon Xpress 200 IGP's R300 roots and Catalyst drivers not only ensure broad compatibility with existing games, they also come with an array of video deblocking and playback acceleration features, as well as solid multimonitor capabilities.

Despite its attractive feature set, motherboard manufacturers have been slow to release retail products based on the Radeon Xpress 200 chipset. Shuttle hasn't shied away, though. The small form factor originator has a history of aggressively implementing new core logic chipsets, and they've come up with a cube based on the Radeon Xpress 200. With DirectX 9-class integrated graphics, dual monitor outputs, PCI Express, High Definition Audio, and a striking brushed aluminum chassis, the ST20G5 promises to be the most well-rounded XPC for Athlon 64 processors. Read on to see if the system lives up to its potential.

The specs
As usual, we'll kick things off with a look at the ST20G5's spec sheet. We'll only be covering the highlights here; for a more in-depth look at the Radeon Xpress 200, see our review of the chipset.

CPU support Socket 939-based Athlon 64 processors
Chipset ATI Radeon Xpress 200
North bridge ATI RS480
South bridge Uli M1573
Interconnect 1GB/sec (2 lanes PCI Express)
Expansion slots 1 PCI Express x16
1 32-bit/33MHz
Memory 2 184-pin DIMM sockets
Maximum of 2GB of DDR266/333/400 SDRAM
Storage I/O Floppy disk
1 channels ATA/133
2 channels Serial ATA with RAID 0, 1 support
Audio 8-channel audio via Uli M1573 south bridge and Realtek ALC880 codec
Ports 1 PS/2 keyboard
1 PS/2 mouse
USB 2.0 (rear)
2 USB 2.0 (front)
1 Firewire via VIA VT6307 (rear)
1 Firewire (front)
1 RJ45 10/100/1000 Gigabit Ethernet via Broadcom 5751

1 analog front out
1 analog bass/center out
1 analog surround out
1 analog rear out
1 analog line in
1 analog mic in (front)
1 analog headphone out (front)
1 digital S/PDIF output (TOS-Link)
1 digital S/PDIF input (TOS-Link)
BIOS Phoenix AwardBIOS
Bus speeds HT: 200-232MHz in 1MHz increments
DRAM: 100, 133, 166, 200MHz
LDT: 1000, 800, 600, 400, 200MHz
Voltages CPU: auto, 0.8-1.7V in 0.05V increments
DDR: auto, 2.7-2.9V in 0.1V increments
Chipset: auto, 1.85-1.95V in 0.05V increments
Monitoring Voltage, fan status, and temperature monitoring
Fan speed control CPU/System

The ST20G5 is built around a core logic combo of ATI's RS480 north bridge and ULi's M1573 south bridge. It's rare to see north and south bridge chips from different companies working together like this, but ULi designed the M1573 to complement ATI's latest north bridge chips. It also helps that the RS480 is designed to interface with a south bridge chip over a pair of PCI Express lanes rather than over a proprietary interconnect.

With the Athlon 64's memory controller sitting on the CPU die, the RS480's biggest features are its PCI Express interface and integrated graphics processor (IGP). Looking at PCI Express, the RS480 serves up 20 lanes of connectivity in addition to the two lanes it uses for a north/south bridge interconnect. The ST20G5's PCI-E x16 slot consumes 16 of those lanes, with an additional lane used by the system's Broadcom 5751 Gigabit Ethernet controller. That's it for PCI Express; although the chipset has PCI-E lanes to spare, Shuttle has opted to equip the cube with a standard 32-bit, 33MHz PCI slot instead of a PCI-E x1.

The RS480's biggest claim to fame is its integrated graphics processor, which is based on the same RS300 core architecture that ATI has been riding since the Radeon 9700. R300 heritage gives the RS480 IGP full DirectX 9 support, although the chip only has two pixel pipelines running at 350MHz. Even so, the Radeon Xpress 200 IGP has already proven superior to Intel's GMA 900 IGP. The Radeon Xpress 200 doesn't really have any DirectX 9-class competition on the AMD side of the fence, either.

Some Radeon Xpress 200 graphics configurations add a bit of RAM on the motherboard to boost performance. The ST20G5 doesn't have any "SidePort" RAM chips onboard, so the IGP will have to use only shared system memory for its frame buffer.

As far as features go, the Radeon Xpress 200 north bridge is reasonably current. The same can be said for the ST20G5's ULi 1573 south bridge, which supports Intel's "Azalia" High Definition Audio standard and Serial ATA RAID with Native Command Queuing. While RAID and NCQ are nothing new, the ULi 1573 is the first south bridge chip to bring 32-bit/192kHz audio to the Athlon 64.