It has only been a few months since Athlon processors based on AMD's AXIA stepping were all the rage. With the Athlon 1.4GHz, we're introduced to yet another new stepping: AYHJA. Based on our experience with AXIA chips (which were already hitting 1.4GHz in many cases), we were pretty enthusiastic of the overclocking potential of our processor.
The core up close
With this in mind, the first goal we shot for was 1.5GHz. Based on the bus options present on our AD11, the shortest way to get there was 1518MHz (11x138). Luckily we accomplished this with no problems at default voltage. Next, we tried raising the clock multiplier to 11.5x resulting in a final clock speed of 1587MHz. Unfortunately, we couldn't get 1587MHz to run stable, regardless of the core voltage we attempted.
Slowly but surely we lowered the system bus/clock multiplier combination until we settled for 1533MHz, the highest setting we could run stable.
Normally we'd be grateful with a 133MHz overclock, after all, the extra processing power came for free! Strangely enough however, our 1533MHz max was accomplished with default voltage, 1.75V. Even our attempts to get 1540MHz (11x140) completely stable were unsuccessful. Based on our success with default voltage, perhaps we got one of the slower AYHJA chips? In all honesty, there's no real way to know. After all, nothing is guaranteed with overclocking.
With the higher clock speed of the Athlon 1.4GHz comes additional challenges of keeping the processor cool. To date AMD's validation unit has approved only 15 cooling solutions. One of them is Foxconn's PK0451AEDAUFB, the same unit we tested with the Athlon 1.33GHz a few months ago.
validated for use at 1.4GHz
We've found Foxconn's cooler to be very effective at keeping our Athlon 1.4GHz cool, the average temperature we witnessed at 1.4GHz was 125°F while the system was under load.
In any case, if you plan on purchasing a 1.4GHz Athlon, make sure to check out AMD's list of approved heatsinks in advance of picking up your parts. At the very least, the list will narrow down your selection of heatsinks to choose from.