Since AMD's Phenom launched last November, the processors' uptake among enthusiasts hasn't been quite as, er, phenomenal as AMD might have hoped. We think there are several reasons for this apparent disinterest, including these two key issues:
- Since the ATI acquisition, AMD has largely focused on its own chipsets and platforms. AMD's chipsets may have some appealing features, but the upgrade path for users of existing Socket AM2 systems based on chipsets from Nvidia (and others) hasn't been entirely clear. Information about nForce-based motherboard compatibility with the Phenom, and the BIOS revision levels needed, has sometimes been difficult to find.
- Compounding this problem, another set of questions has been even tougher to answer: Will my motherboard's BIOS include the TLB erratum workaround, which significantly impairs Phenom performance in many tasks? If so, will I have the option of disabling the workaround rather than suffering the performance hit? And if so, how? We've likened disabling the erratum workaround to overclocking—a calculated risk that's probably worth it for most enthusiasts. AMD does let users disable the fix via its OverDrive tool, but that tool only works on motherboards based on AMD's own chipsets. Also, the option in the OverDrive utility is unlabeled and largely undocumented. (Users must click the large round button at the top right of the OverDrive window. If the button turns yellow or red, the TLB fix is disabled.)
We expressed concern about these issues in our article about the Phenom 9600 Black Edition and elsewhere. AMD offers a motherboard compatibility list on its website, but it currently includes only 17 motherboards. Fortunately, the firm seems to have taken our criticism to heart. The CPU maker decided to help us compile a much more exhaustive list of motherboards from major manufacturers that have Phenom support and/or an option to disable the TLB erratum fix.
We're bringing you that list to you now as an exclusive. AMD worked with us to put it together, and we've verified what we could. Boards with a "Y" in the AMD-tested column have been tested for Phenom compatibility by AMD itself, while the others have Phenom-ready BIOSes supplied by the motherboard makers. Similarly, boards with a "Y" in the "TLB fix switch "column should allow users to disable the TLB erratum workaround—either via a BIOS-based switch or, in the case of AMD chipset boards, via the Overdrive utility. Those with a green Y were confirmed by AMD to have such an option, while those with a white Y were vouched for by mobo makers.
|Manufacturer||Motherboard||AMD tested||TLB fix switch|
|M2N32 WS PRO|
|MSI||K9A2 Platinum (MS-7376)||Y||Y|
|K9A2 CF (MS-7388)||Y||Y|
|K9N Neo-F V3 (MS-7369)||Y|
|K9N SLI-F V.2 (MS-7390)|
|K9AG Neo2-Digital (MS-7368)|
|K9N Neo V2 (MS-7369)|
|K9N Neo V3 (MS-7369)|
As you can see, many older nForce motherboards should have no trouble working with the Phenom, and some of them even have options to disable the TLB erratum fix. Gigabyte seems to have the most boards with a fix switch setting, which has almost assuredly been implemented at the BIOS level.
What we're seeing here today isn't just extremely useful information for potential Phenom buyers. The release of this information also signals something of a change of direction for AMD, and we're hopeful the company will begin paying more attention to the needs of enthusiasts and would-be upgraders. In the coming weeks, we expect to see a number of BIOSes released for Socket AM2 and AM2+ motherboards that offer the option of disabling the TLB workaround. With luck, most owners of Socket AM2 systems should soon have enough information to confidently take advantage of what looks to be a heck of a deal on a quad-core processor.
Update March 14, 2008: The list above originally suggested that several motherboards based on AMD 690-series chipsets would allow users to disable the TLB erratum fix. We've since discovered that only two of them—Gigabyte's GA-MA69G-S3H and GA-MA69GM-S2H—actually have such an option, while others do not. See our news post about the subject. We have updated the table above to reflect this new information. We regret the error.