Socket 939 Chipsets: Motherboard Performance & PCI/AGP Locks

Final Words

The last time we compared Dual-Channel chipsets on Athlon 64 was in our Socket 940 roundup. At that time, nVidia was hampered by a 600 Hyper Transport bus on their nForce3-150 cipset and VIA emerged as the clear winner. Things have changed quite a lot since that 940 comparison, particularly for nVidia. Both chipsets now sport the same 1000 HyperTransport that is specified for the new Socket 939. nVidia has also added many cutting edge features, such as on-chip Gigabit LAN and a unique on-chip Firewall. nVidia also has added up-to-date features to nF3-250, so the chipset now compares very well to the best chipsets in the market, and they also fixed one of the trademark nVidia features - the AGP/PCI lock (or asynchronous operation). As we saw in our recent Socket 754 roundup, the AGP/PCI lock not only worked on every nForce3-250 motherboard that we tested, but this feature proved to allow some of the highest overclocks that we have yet achieved on Athlon 64.

VIA, on the other hand, has done little to improve on the K8T800 PRO chipset in the past year. The PRO version adds 1000 HyperTransport and claims to have added VIA's first working PCI/AGP lock to the K8T800 PRO features. VIA would point out, and we would agree, that the K8T800 was already a superior chipset and that a long list of improvements were not needed as they were on nVidia's first nF3-150 chipset. However, nVidia's nForce3-250 Ultra is a stiff competitor in the latest round of Athlon 64 chipset updates and as a result, VIA needed to bring all the features that they could to the table for this round.

While we are here at Computex, we have been able to talk with many manufacturers about the PCI/AGP locks on the VIA K8T800 PRO and the nVidia nForce3-250. We have also talked with VIA. Right now, the PCI/AGP lock works on every nForce3-250 chipset that we have tested, while it works on some VIA K8T800 PRO chipsets, but does not work on others. It appears from the information we have right now that the VIA PCI/AGP lock is not a reliable or consistent feature on the K8T800 PRO chipset. Since this is an important feature to many Enthusiasts, who are a large percentage of readers at AnandTech, our advice FOR NOW is to buy an nForce3-250 chipset if the PCI/AGP lock is an important feature in your Athlon 64 purchase decision.

As you clearly saw in our performance tests of the K8T800 PRO and nVidia nForce3-250, the performance is very close between the two chipsets on the Dual-Channel Socket 939. VIA is slightly faster on many of the standard gaming benchmarks, while nVidia is the better performer in Workstation Graphics. The chipsets trade wins in our General Performance and benchmarking tests. If everything else were equal, we would have concluded that the battle is a toss-up, and you should choose either chipset for 939 based on features that were important to you. For absolute best performance, we would say VIA is slightly faster in general, but nVidia is clearly the better performer in Workstation graphics.

However, the PCI/AGP lock confusion has to enter into our recommendations. If the PCI/AGP lock is not an important feature and you do not plan to overclock, then you can safely choose either the VIA K8T800 PRO or the nVidia nForce3-250 Ultra chipset for your new Athlon 64 motherboard. In fact, if you do not plan to overclock at all, the VIA K8T800 PRO is slightly faster than nForce3-250, though the difference is so small that it is of no real consequence. However, if a working PCI/AGP lock is important to your buying decision or you intend to more than mildly overclock the Athlon 64, you should buy an nVidia nForce3-250 Ultra motherboard. Until VIA can fix the teething problems with their new PCI/AGP lock feature for Athlon 64, we cannot recommend the K8T800 PRO for those buyers looking for the PCI/AGP lock feature. This will likely be corrected in the future and we will take another look at VIA asynchronous capabilities as soon as we can verify that this is a consistent and reliable feature on the K8T800 boards.