ASRock 890FX Deluxe: Comprehensive Motherboard Review & Investigation of Thuban Performance Scaling

Timed with Phenom II X6 CPU launch, AMD introduced a new platform to go along and dubbed it “Leo”.  Essentially, the Leo platform is comprised of the the following:  Phenom II CPU,  890GX/890FX motherboard, and Radeon HD 5800 series video card.  Instead of the obvious marketing, we are focusing on what has changed on the 890FX from the 790FX.  The improvements are rather sparse, but there still are meaningful improvements on Leo platform over previous generation platforms and we covered some of those in the past. 

While the changes are subtle, they are just about enough to make the 890FX the most advanced desktop chipset today.   The most significant contributions lie in the amount of PCI Express 2.0 at its disposal as well as the official support of SATA 6.0 Gbps standard.  Not only does it provide the most PCIe bandwidth, but from what we’ve seen most board makers opt to utilize the PCIe 2.0 lanes stemming from the north bridge for the boards’ PCIe slots and peripheral controllers unlike Intel’s PCH-based solutions that rely on PCIe 1.0 bandwidth then have to go through slow DMI bus.  On ASRock’s 890FX Deluxe 4 we had no problem fully saturating the total available 42 lanes.    

However one thing we find somewhat dubious is AMD’s claim of 5.2 GT/s  of HyperTransport bandwidth.  The HyperTransport bandwidth is closely related to the CPU-NB (CPU’s Integrated memory controller) frequency as we will see later, and in order for HyperTransport bus to supply 5.2 GT/s of bandwidth the CPU-NB should be running at 2.6 GHz or faster.  We do not know of a shipping AMD CPU with its CPU-NB at 2.6 GHz, so that kind of makes the 5.2 GT/s claim meaningless.  To be fair, the claim is on the chipset not on the CPUs, and we did not have trouble running ASRock 890FX Deluxe 4 @2.6 GHz HT Link frequency along with our retail 1090T’s CPU-NB @2.6 GHz.

The interconnect between north bridge and south bridge, A-Link, has been upgraded to PCIe 2.0 standard from PCIe 1.1 on 790FX/SB750 combo.  The new south bridge, SB850, is indeed what steals the spotlight, providing six native SATA 6.0 Gbps ports and whooping 14 USB ports.  It also retains its RAID capability from its predecessor, but we advise against complex RAID setups like RAID5 or RAID10 on chipset-based controllers.  AHCI standard received an upgrade as well, from V1.1 to V1.2.

IOMMU is an acronym of Input-Output Memory Management Unit, and it is supposed to make virtualizing I/O such as the storage subsystem or video cards possible.  Even though virtualization is gaining traction on desktops thanks in part to Windows 7’s XP Mode, desktop virtualization is still limited on CPU virtualization. We are still some time away from I/O virtualization on desktops, and in any case we’re not aware of any client Windows OS that support I/O virtualization.  So this remains a check-box feature for now.

We are unsure as to why TDPs have increased for both 890FX and SB850, but without AMD disclosing datasheets for those we are left, well, unsure.  We assume they did go up considering that AMD heavily touted 10W TDP for 790FX at its launch.  This time AMD is rather silent on the TDP front.  Lastly, we see AMD’s first gigabit controller native to SB850, but we haven’t seen any board that uses it.