Conclusion
Not yet an upgrade option: AMD's Phenom processor. Only Asus has provided BIOS updates to support the new quad core on mature motherboards.
I don't really like the conclusion and AMD won't like it either, but the upgrade situation for users interested in replacing their Athlon 64 X2 processor with a quad core Phenom is all but promising Compare Prices on AMD Phenom Processors. We looked at ten different motherboards to check how well these would work with the new Phenom quad core processor. The vast majority, eight out of ten motherboards, did not work with Phenom at all, which I found a very frustrating result. Yes, Phenom has only been available for roughly one month, and AMD is busy bug-fixing the TLB issue, which certainly came at a difficult moment. However, not being able to run the new processor on existing platforms, as promised by AMD, is both disappointing for those users still interested in using a quad core Phenom processor right away, as well as for AMD, who critically depends on selling its new product.
This result is independent from the chipset used, or from the price category or market segments the motherboards were in. Only Asus and Gigabyte were quick enough to provide a BIOS update, which officially declares Phenom support. However, Gigabyte only provides the update for a mainstream product, but not for the enthusiast model we also looked at. To make things worse, the Gigabyte Phenom update for the mainstream motherboard did not work - at least it doesn't on the 0.2 pre-release sample we had at our disposal for this test.
Motherboard makers such as Biostar or Epox haven't followed up with BIOS versions for their products for some months; others such as Foxconn or MSI simply have not yet released updated BIOS versions with Phenom support. The successful Phenom upgrade on the two Asus motherboard leaves no doubt that even older socket AM2 products are capable of running the quad core Phenom. In the end, the matter of supporting the new processor comes down to time to market from a support standpoint. It's difficult to say if it is AMD who could have done more to facilitate BIOS updates, and if the TLB bug had an influence on BIOS releases. It is likely that some motherboard makers prefer to wait with releasing Phenom enabling BIOS updates until the workaround can be implemented.
Eventually, the reasons for the lack of Phenom support are secondary. Looking at the results and BIOS resources available on the web, we cannot recommend to upgrade existing socket AM2 systems from Athlon 64 X2 to Phenom right away. Our recommendation hence is simple: Keep your Athlon 64 X2 if you can and wait for the Phenom B3 stepping. Not only will it fix the TLD bug, but we expect most motherboard manufacturers to be ready with proper Phenom support by then.
Update:
AMD has informed us that there is a list of recommended motherboards for Phenom. The list is available on its website:
As of January 3rd we found 17 motherboards with guaranteed Phenom compatibility. While this is better than nothing, most of these recommendations are based on rather new chipsets. There will be more and more motherboards compatible with Phenom soon, but it is obvious that compatibility for older motherboards still isn't where it could be.
