More CPUs/Overclocking

In addition to the new dual-core CPUs, today AMD is also introducing new energy efficient quad and triple core processors.

The Phenom II X4 905e is AMD’s first energy efficient Phenom II quad-core processor. Clocked at 2.5GHz, the chip ships with 512KB of L1 cache, 2MB of L2 cache (512KB of L2 cache per core), and the full 6MB of L3 cache found on AMD’s flagship Phenom II processors. Max TDP comes in at just 65W according to AMD. The chip is priced at $195.

For the triple-core crowd, AMD offers the Phenom II X3 705e. Like the 905e, the Phenom II X3 705 runs at 2.5GHz and sports the full 6MB of L3 cache found on faster Phenom II processors. AMD also lists a 65W TDP for this processor, which will be priced at $125.

Availability

AMD says that they’re stocking vendors with all of today’s newly announced processors as we speak. AMD expects retail availability within one week from today.

Picking a platform for testing: Gigabyte’s GA-MA770-UD3

As anyone who has shopped the AM3 market can tell you, there’s a dearth of inexpensive motherboard options out there. Most of the motherboards that have actually hit retail shelves so far are high-end $150+ 790FX motherboards. There are also a handful of 790GX motherboards out there as well, but they’re still selling for well over $100: we doubt many enthusiasts would be willing to spend $110+ or more on a motherboard to pair with their $102 Phenom II X2 550 or $87 Athlon II X2 250. It just doesn’t make sense to spend more money on your motherboard than your CPU, when it’s the CPU that’s going to play a bigger role in overall performance.

Fortunately an increasing number of motherboards based on AMD’s 770 chipset are beginning to hit the market. We chose to run our testing with one of the first, Gigabyte’s GA-MA770-UD3.

Priced at just $85 on Newegg right now, the GA-MA770-UD3 supports DDR3 memory speeds of up to 1600MHz, more than enough to get your feet wet when OC’ing your memory. Meanwhile HyperTransport options top out at up to 500MHz in 1MHz increments, giving you more than enough options in this department as well. As its UD3 designation implies, the GA-MA770-UD3 incorporates Gigabyte’s latest Ultra Durable 3 features, including 2-ounce copper PCB, all-solid Japanese capacitors, ferrite core chokes, and more.

Basically it’s a nice option if you’re looking for a motherboard that’s inexpensive, yet well featured, with very good performance and excellent stability. We ran into some stability issues running AMD’s Overdrive utility while OC’ed (the utility appeared to cause the system to crash from time to time), but other than that we didn’t encounter any issues during testing. Because of this issue though, we did elect to OC our processors the old-fashioned way: via BIOS. We’re such huge fans of AMD’s Overdrive utility we normally use it exclusively for all our overclocking endeavors.

Overclocking

With its unlocked clock multiplier, the CPU we were most interested in testing was AMD’s Phenom II X2 550 Black Edition. We were eager to see if we could get the chip to run 4.0GHz or more with complete stability.

While we had no problems getting the system to load Vista 64-bit at such high speeds, and could even run some apps at 4.02GHz, we couldn’t get complete stability with all of our apps at that speed. Even at 4.0GHz we couldn’t get everything to run completely stable. We even tried cranking the CPU voltage up to 1.61V, but to no avail. 3.9GHz (19.5x200) ran completely stable though. At this point, we called it a day assuming we’d narrow down a final stable speed somewhere between 3.9-3.99GHz. Unfortunately, things took a turn for the worse the next day.

The next morning, the system wouldn’t even load Vista at 3.9GHz. Every time we tried to boot the OS, we were greeted with a BSOD shortly after loading the Vista splash screen. We tried everything in the book to get the OS to load, but nothing worked. Not even extreme voltages. This completely baffled us because the day prior we didn’t have any problems loading the OS until speeds approached 4.1GHz. We had just run looped Crysis runs at 3.9GHz for an hour the day prior. Now we couldn’t even get the OS to boot at that speed!

So what speed did we settle on? 3.829GHz (18.5x207). Still not a bad OC, but considering where we’d been, it was pretty disappointing to say the least.

We don’t have a dramatic overclocking tale for the Athlon II X2 250 as we were forced to rely on its stock voltage when OC’ing. In addition, with its fixed multiplier, you’re forced to rely on the HyperTransport interface alone, which as any experienced AMD OC’er can tell you, doesn’t scale like the FSB used on Intel’s Core 2 Quad CPUs. Ultimately we maxed out at 3.39GHz (15.0x226).


Here we think we were held back a little by voltage, but obviously the CPU isn’t going to OC like a processor with an unlocked multiplier will. BIOS updates to the GA-MA770-UD3 will hopefully bring more voltage options to Athlon II users in the future.