AMD's latest chip is very attractively priced, but there’s not much else to really grab anyone's interest?
Suffice to say, AMD have not had such a rosy time in the CPU business of late. While their products aren't bad (and indeed fill an essential hole in the market), it's very hard for an enthusiast to look to them for most of our needs - namely, the best darn performance we can grab. This doesn't blow out to the other end of the scale, either, and rather we mean a chip that does all you want it to for the right price. The Athlon II X2 255 certainly appears as an appealing processor at the pricepoint of only a hundred dollars; at this level it seems almost an impulse buy, rather than a full-blown CPU purchase. We'd reckon that's because it isn't a full-blown CPU - at least, not in the way that we define processors.
Taking a quick look at the specifications for this chip is all you really have to do to get an idea of its ultimate performance. Based upon the same Phenom II die that all the II series chips are, the Athlon II 255 is bequeathed the 'Regor' version of the die. This contains the same amount of transistors as AMD's top-end chip, but due to partial faults in manufacturing, two of the cores have been deactivated. For those budget-conscious folks out there, these budgetesque dual-core processors possess great potential for a motherboard with an unlocking tool, but getting access to those cores is not 100% reliable.
128KB of L1 cache sits at the heart of each core, split down the middle into two identically sized pools for Instruction and Data sets. The budget nature of the Athlon kicks in again when we hit the L2 cache; a measly 1024KB per core for a total of 2MB. While the L2 cache can be shared between the two cores depending on workloads, it's still pretty abysmal. A locked multiplier of 15.5 is actually pretty nice, giving a stock speed of 3.1GHz at a pretty low TDP of 65W. With the jump to the AM3 socket practically complete, the chip uses this new socket alongside DDR3 memory.
The memory performance is one of the nicest features of this chip; returning pretty great bandwidth scores for the price, as well as a latency that gives Intel's high-end chips a run for their money. Unfortunately, this dual-cored chip simply lacks the grunt to make any noticeable headway against even Intel's budget I3 540 chip; slow PiFast results match up with a similar slowness in every single-threaded app. Multithreaded applications are handled with aplomb, but quite a small plomb, since performance only reaches 1.90 times the speed of a single core. Clearly, AMD would benefit from something similar to Hyperthreading.
Luckily, budget processors are infamous for their overclocking prowess, and the 255 isn't much of a slouch in that aspect. We threw it underneath a decent heatsink and pushed clocks harder than a drug dealer at an electrofunk concert, hitting a ceiling speed of 4234MHz using 15.5x278 at 1.45V. This is an impressive speed increase, but it came at the expense of an aftermarket heatsink. When building to a budget this is something to avoid, and it makes more sense to spend a little more on the Phenom II X4 620 for not many more dollars. Overall, the 255 isn't worth your time.
Issue: 137 | June, 2012