Our USB transfer speed tests were conducted with a USB 2.0/FireWire external hard drive enclosure connected to a 7,200-RPM Seagate Barracuda 7200.7 hard drive. We tested with HD Tach 3.01's 8MB zone setting.
The SB850 may have a rearchitected USB controller, but it's not as fast as the one inside the H55 Express. The 890GX boards pull up short in the burst and average read speed tests, and the Gigabyte trails behind the leaders with writes, too.
Matters get worse for the Gigabyte board when we look at CPU utilization, which is notably higher than the Asus. The 890GX boards are both running the "Balanced" Windows power plan with Cool'n'Quiet enabled, so there shouldn't be this much of a difference between them.
When asked about the SB850's slower USB transfer rates, AMD suggested that real-world transfers shouldn't be affected. The company also indicated that Cool'n'Quiet can react oddly to CPU utilization tests, although that wouldn't explain the difference in CPU utilization between the Asus and Gigabyte boards.
PCI Express performance
We used NTttcp to test PCI Express Ethernet throughput using a Marvell 88E8052-based PCI Express x1 Gigabit Ethernet card.
To test PCI performance, we used the same NTttcp test methods and a PCI Intel GigE NIC.
A Gigabit Ethernet controller may not be the most bandwidth-intensive peripheral to throw at an expansion interface, but it's certainly the most common. All of our system configurations do well in the throughput tests, but the 890GX rigs have higher CPU utilization than the H55 Express. I suspect we're seeing the Athlon II's clock throttling in action again, but that doesn't explain why the Asus board has lower CPU utilization than the Gigabyte in the PCI test.
That covers the chipset-specific portion of today's festivities. Now it's time to switch gears to exploring variables more dependent on motherboard attributes than core-logic components. First up, we have power consumption tests. We measured system power consumption, sans monitor and speakers, at the wall outlet using a Watts Up Pro power meter. Readings were taken at idle and under a load consisting of a Cinebench 11.5 render alongside the rthdribl HDR lighting demo. We tested with Windows 7's High Performance and Balanced power plans.
Motherboard makers usually ship their boards with energy-saving software that's supposed to lower power consumption without impeding performance. We've tested each board with and without this software installed. Gigabyte's H55 Express board uses Dynamic Energy Saver software, while the company's 890GX offering uses a new app called EasySaver. The Asus board uses an EPU app that must be configured in "auto" mode to avoid performance-sapping clock throttling.
Even with fewer power phases than its Asus counterpart, the Gigabyte 890GX board draws notably more power. Running each company's power-saving software is good for a watt or two, but that's about it.
As one might expect, our H55 system has the lowest idle power draw of the lot. The Core i3-530 is more power-efficient than the Athlon II X4 635, and the Intel CPU is also running on a smaller microATX motherboard.
Under load, the Intel system has even more of a power-efficiency advantage. It's not even close.
Between the 890GX boards, the Asus draws less power under load by about 10W. Power-saving software has more of an effect here than it did at idle, particularly on the Asus board.