nForce4 Ultra Roundup: Charting the Mainstreamby Wesley Fink on July 5, 2005 10:28 PM EST
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Processor ArchitectureAnother concern has surfaced in the last few months that should be a consideration for anyone shopping for an Athlon 64 motherboard - the processor factor. When we tested the nForce4 SLI boards, we used the 4000+ Clawhammer chip as our standard CPU. We also had done some testing with the early Winchester and Newcastle chips, which were based on the 90nm production process instead of the 130nm process used for Clawhammer. Overall, these early 90nm chips were mainly a die-shrink, and performance - and compatability - were much the same whether it be the Clawhammer, Winchester, or Newcastle.
Recently, however, we have some new choices from AMD in Revision E chips and dual-core. These new Revision E parts support SSE3, are based on the 90nm process, and they do not always behave as earlier chips did in the same motherboard. We saw this for ourselves in our Gold Editor's Choice MSI K8N Neo4/SLI. While we experienced outstanding overclocking with a Clawhammer chip, users with Venice/San Diego chips were experiencing perfectly miserable overclocking results. It has taken MSI some time to find a solution to this problem, but we are happy to report that a new BIOS has just been released that claims to fix the Venice issues on the MSI.
The point of this is that the newest Athlon 64 Revision E chips do behave differently than earlier Athlon 64 chips in some boards. This is likely a temporary concern as the market adjusts to the newest CPU architectures, but it is a factor that should be considered.
This becomes an even larger issue with the new Manchester/Toledo dual-core chipsets. The Athlon 64 X2 joins two Venice or San Diego cores on a single CPU. These Revision E X2 dual-core CPUs (the 4200+, 4400+. 4600+, and 4800+) generally will work in any Socket 939 board. However, you will certainly need at least a BIOS upgrade. Most of the major manufacturers have quickly brought the needed BIOS upgrades to market, but if you plan to run a dual-core chip, you need to check before you buy.
We approached these issues in this roundup by continuing our benchmarks with the Clawhammer-based 4000+ processor - to allow the greatest comparison to earlier motherboard reviews. However, we also checked each board with a Manchester 90nm 4200+ CPU. This required finding the latest BIOS for x2 support, which we have also listed in the Motherboard Features chart for each board. This tells you the earliest BIOS revision that has been said by the manufacturer to support the X2 dual core chips.
It should also be mentioned that AMD has implemented a hidden feature in Revision E processors, namely additional memory ratios that can be implemented in BIOS. As we had seen on the Abit motherboard in this roundup, a Revision E chip adds 433, 466, and 500 options to the available memory ratios. This has to be coded in the BIOS to be available, but the new asynchronous ratios are a feature of the Revision E Memory Controller. We identified 2 boards, the Abit and DFI, that correctly implemented this function with the Rev. E chips and included that information in the feature table.
The good news is that just about any Socket 939 motherboard can run dual-core, and every motherboard in this roundup had a BIOS very recently available to support AMD x2 processors. But you will more than likely need a BIOS update.
How to Update BIOS for Dual-Core if You Have Dual-Core OnlyThis brings up the nagging question that is always asked when BIOS upgrades are required for certain CPUs. What do you do if you have a board that needs a BIOS upgrade for dual-core and you only have a dual-core chip? We asked AMD this question and was given the following reply:
"If the BIOS you are working with (original BIOS in the board) supports a rev E single core (AKA... 90nm as most new boards should), it will allow you to flash the BIOS to a BIOS that supports rev E dual core. In my experience, a DC processor with single core rev E support will run fine, but only as a single core. If the BIOS doesn't support rev E (In other words, you may have a good board, but the BIOS is pretty old), you will likely need to install a pre-rev E (AKA-130nm) AMD processor to flash the BIOS.
I'm told that if a customer can't flash their BIOS, many mobo vendors will mail out the BIOS chip to them (if it's not soldered down, obviously)."