Triple Troubles

When AMD sent me the triple core Phenom 8750, I was expecting to throw it in a Phenom compatible motherboard and be off to the races. Unfortunately, my experience was not quite that simple.

I had an AMD 770 series based motherboard handy in the lab that I was going to use for testing. Seeing as though this board was designed with Phenom in mind, I thought it should work without incident. I had no issues getting the board to post and it even recognized the CPU as “AMD Phenom X3 8750 Triple Core” during the boot process. To my frustration, however, the system consistently hung during the Windows Vista installation.

I was pleased to see that a new BIOS had just recently been published for this board—the timing seemed to coincide with the launch of the new 9x50 series Phenom X4 processors. After flashing to the latest revision, I was able to install Vista. Once I took a look at the task manager, however, I was greeted with a bit of a surprise.

Last I checked, this should have been a triple core CPU. As far as this system was concerned, there were only two CPU cores, not three. CPU-Z 1.44.2 correctly identified the Phenom X3, but indicated that there were only two cores also.

Coincidentally, AMD let all the X3 testers know about a recent Microsoft KB article outlining a problem in Vista and Server 2008 where a CPU may use fewer processors than expected if the number of cores on a socket is not a power of 2. It is listed as KB950182 for anyone interested in learning more. Well, three is not a power of two, so I was off to retrieve the hotfix, or so I thought. The hotfix was not released to the general public, so I had to open a support case with Microsoft to obtain the patch. After applying it, however, I had the exact same problem. This was not a Microsoft issue at all in my situation, but rather a lower level issue with the board. It looks like an additional BIOS update will be necessary to get a triple core Phenom working with this particular board. I discussed this hotfix with AMD and they indicated that the average consumer need not worry about this hotfix. It is likely a solution to a very one-off problem experienced.

I decided to give the X3 a shot in an older socket AM2 based board based on a nvidia chipset as well. It was flashed to the latest BIOS that enabled Phenom support. Despite my attempts, I could not get the system to post with the X3 installed.

These issues are really not AMD's fault, but buyers need to be aware that not all boards will support the Phenom X3 out of the box. Even newer boards based on AMD's 7 series chipsets may require a BIOS update.

AMD provided us with a list of suggested boards for X3 testing, but I did not have any of those particular models in the lab. Most of them were based on AMD's new 780G chipset. I ran out to a local PC shop and was thankfully able to pick up a Gigabyte GA-MA78GM-S2H board in time to do some benchmarking. I updated the Gigabyte BIOS to revision F3 that is available at their website and had no issues getting all of the cores recognized. The KB950182 hotfix was not required.

Software Scaling Issues

Things seem to consistently double in the world of PCs. One gigabyte to two gigabytes to four gigabytes, and so on. The same seems to be holding true for CPU cores. One, two, four, eight and so on. It seems that many software developers have been assuming that CPU makers would be holding true to this pattern. As such, certain applications that do indeed take advantage of dual and quad core processors, do not always take advantage of triple-cores. Windows Media Encoder 9 for example, gladly takes advantage of 1, 2 or 4 cores, but does not seem to utilize a third. So a triple core scales like a dual core in this situation. AMD is currently working with Microsoft on this specific issue, but I'm sure some others will begin to surface as triple core CPUs enter the mainstream. Although this may prove to be a bit of an annoyance in the short term, reputable software companies will surely begin to patch their applications.