Introduction and Unlocking the Phenom II X2 555
Price: £75 inc VAT
Best Price: http://pricebomb.co.uk
While AMD’s video cards go from strength to strength, the manufacturer’s processor division has struggled recently. Ever since the Core 2 series debuted way back in 2006 the Green Team has been playing catchup, unable to match a resurgent Intel for pace. The original Phenom was a huge disappointment and although its replacement is far better, the Phenom II is still no match for Intel’s Core i5 and Core i7. AMD is therefore focusing its efforts on the budget sector where the firm's products become far more interesting. Whilst we are hopeful for a new architecture at some point this year, for now it’s just a case of minor speed bumps as yields improve.
Today we are looking at the Phenom II X4 555; a new processor designed to go up against Intel’s Pentium dual cores at the important £75 inc. VAT price point. Intel would no doubt prefer us to pitch this chip against its Core i3 530, but as that CPU costs 20% more it wouldn’t be a fair comparison. In actual fact the closest contemporary competitor is the Pentium G6950, which also uses the Clarkdale core. Intel released this chip rather quietly, obviously mindful that without blistering clock speeds the chip isn’t as competitive as the rest of the range. Either chip can be snapped up for around £75 from the cheapest online sources.
The 555 boasts a speed bump to 3.2GHz over previous models in the Phenom II X2 range and has the same allocation of L1 and L2 cache at 128k and 512k per core respectively. It also has a shared 6MB L3 cache and, as with all other AM3 chips, is compatible with both Socket AM3 boards and older socket AM2+ variants. If you are upgrading the latter platform you should make sure you update your motherboard’s BIOS before swapping chips. The Phenom II X4 555 Black Edition has a fully unlocked multiplier; a feature that makes overclocking effortless even if you have a modestly specified motherboard.
Four cores for the price of two?
As with previous Phenom II X2 processors the 555 is not a native dual core. Instead, AMD re-badges Phenom II X4s that don’t quite cut the mustard as X2s with two of the cores disabled. If you have a motherboard with a recent AMD Southbridge a nifty feature called ACC can be used to unlock the latent cores and unleash the chip’s full potential. Using our Gigabyte test motherboard we were able to unlock these cores effortlessly. We enabled the ACC mode in the motherboard BIOS and set the EC type to “Hybrid”. On reboot the chip was detected as a “Phenom II X4 B55” by the motherboard and continued to boot Windows 7 normally. All four cores were correctly detected by the operating system and the chip passed a 24 hour stress test of Prime 95 without error. Obviously not all chips will unlock successfully, but most users are reporting success with the 555 BE. If your chip unlocks but fails to boot the OS successfully, try bumping up the core voltage a little.