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AMD Phenom X4 9850 Black Edition

It's fair to say the first batch of AMDs Phenom CPUs were a bit underwhelming. Though they represented decent value for money, due to AMDs cut-throat pricing, and brought some welcome competition to Intel on the quad-core front, the simple fact of the matter was performance wasn't good enough for us to recommend a Phenom over any of Intel's current crop of quad-core CPUs.

Now there can be all manner of reasons why a CPU may not perform as expected, including fundamentally bad design, an inability to run at high enough clock speeds, or thermal limitations, and unfortunately for AMD, it seemed that all but the latter of these problems were plaguing the first Phenoms.

First there was the news of an erratum in the Translation Lookaside Buffer (TLB) that represented a fundamental problem with the design. It wasn't a big issue for most people as the error only threw up problems in the rarest of circumstances - we ran all our tests on the 9600 Black Edition with the erratum unfixed and encountered no problems. However, if you didn't want to run that risk, the software or BIOS fixes that were released caused performance to drop by an average of 10 percent. Whichever option you choose though, it wasn't exactly a good start to the launch.

The other big problem was the fact the early Phenoms simply couldn't run at high enough frequencies. While Intel is happily hitting 4GHz with some of its CPUs, we couldn't get our top of the range 9600 Black Edition to run at over 2.6GHz. Regardless of how superior (or not) the Phenom architecture may be, having such a huge disparity in raw clock speed inevitably impacts on performance.

So, with such a dismal first outing, it was imperative AMD could quickly turn around a tweaked design that fixed some of these fundamental problems. Otherwise any hope of remaining competitive with Intel for the next six months would've evaporated.
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Well, credit where credit's due, that's exactly what the boys in green have managed to do and a couple of weeks ago new TLB error-free Phenoms started hitting shop shelves. These new CPUs basically have a hardware workaround for the TLB problem that, unlike the software or BIOS workarounds, has minimal impact on performance. Indeed, AMD expects performance of the new chips to be the same clock-for-clock as the previous Phenoms when run without the fixes.

Labelled the '50 series', all the new Phenoms will carry clearly distinguishable model numbers from the previous series of Phenoms. Specifically, where old versions had numbering of the format 9x00, the new chips will be of the form 9x50. Also, coinciding with this rerelease, AMD has thankfully decided to reinstate the 'X' in its model names so, once again, tri-core chips will be X3 and quad-core X4. We're really glad to see the return of this nomenclature - we never understood why AMD dropped it in the first place - as we feel it's infinitely clearer than just a model number alone.
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AMD has understandably decided to completely switch production from the old B2 stepping (the previous 9x00 version) to the new B3 stepping (new 9x50 version) and, because of this, the new CPUs are just as competitively priced as the outgoing ones. Indeed, the 9850 Black Edition we're looking at today is exactly the same price as the slower 9600 Black Edition it is replacing.

To confirm, then the Phenom X4 9850 Black Edition is AMD's latest flagship CPU. It runs at 2.5GHz and is manufactured using AMD's 65nm Silicon on Insulator technology, which gives it a nominal TDP of 125W. The big trick up its sleeve, though, is its unlocked CPU/FSB multiplier that gives it a huge amount of potential for great overclocking. It also has one new feature that is exclusive to the 9850, which is a faster memory controller. All the other Phenoms, old and new, have memory controllers running at 1.8GHz whereas the 9850 memory controller trundles along at 2GHz.

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