Socket 939 was AMD's worst kept secret and it cost the company a lot of sales early in the Athlon64's life. After all, who wanted to buy a Socket 754/940 AMD system when Socket 754 was scheduled to become econoline and Socket 940 to be phased out completely? A few adventurous enthusiasts did jump on the bandwagon and gave us some tantalizing numbers which made the wait even more difficult. True to the rumors, about a year after the launch, AMD revamped the Athlon64 line and introduced Socket 939. Since then there has been a flurry of adoption in every sector and 'enthusiast' activities like overclocking have really taken off.

The AMD Athlon64 3500+ is the enthusiast's weapon of choice when it comes to overclocking. A few might argue that going with the Athlon64 3200+ or Athlon64 3000+ is a better deal since you're guaranteed to get yourself a 0.09 micron Winchester core, but I like the higher multiplier that the Athlon64 3500+ offers.

We're going to have a bit of fun with this chip today. We'll test how high our Athlon64 3500+ will overclock with air cooling, but we're also going to put the processor under the deep freeze to see how high it goes with a R404A modded Prometeia Mach I phase-change cooler.

The Athlon64 3500+ being overclocked is a retail specimen and is based on 0.13 micron manufacturing aka the Newcastle core. A Winchester based Athlon64 3500+ probably would have overclocked a bit higher but when you buy retail it's down to the luck of the draw.

AMD Athlon64 3500+ Processor Tech Specs Clock: 2.2GHz L1: 124KB L2: 512KB Multipiler: 11x Package: 939-pin organic mPGA Core: 130nm SOI Transistors: 105.9M Die Size: 193mm2 Vcore: 1.5V Thermal Power: 89W Cost: $258USD Further Technical Details: CPU-to-Memory Controller: 2.20GHz Memory: Integrated 128-bit wide memory controller Types of Memory: PC1600, PC2100, PC2700 and PC3200 DDR HyperTransport Links: 1 HyperTransport Spec: 2GHz (2x 1000MHz / DDR) Effective data bandwidth: Up to 14.4 GB/sec (8GB/sec) HyperTransport bandwidth plus 6.4GB/sec memory bandwidth) Fab location: AMD's Fab 30 wafer in Dresden, Germany Ambient Case Temp: 70 degrees Celsius Max Icc (processor current): 57.4A

As you can see, this Athlon64 3500+ is based on the 'CBAXC' core and was built in week 37 of 2004. Included with the package is a quiet aluminum heatsink as well as some documentation and the cool Athlon64 case sticker. We're going to skip our usual technology discussions and go straight to the overclocking. If you'd like to learn a bit more about what makes the Athlon64 go, please read PCSTATS Athlon64 4000+ processor review.

Ladies and Gentlemen, Start Your Engines!

A bit of setup information first; the motherboard for this test was the DFI LANParty NF4 SLI-DR, the DDR memory was Corsair's PC3200XL series. I selected this board for its awesome overclocking and voltage adjustment options. The Hypertransport speed was kept at its default 5x and the memory was running in sync with the motherboard clock speed (unless otherwise stated) with timings of 2-2-2-5. Memory voltage was set to a higher than normal 3.4V, Chipset voltage at 1.8V and LDT to 1.5V throughout all testing. These voltages were chosen because I didn't want the memory flaking out before the motherboard or CPU did. The above settings apply to both the air-cooled and phase change-cooled overclocking tests.

For the air-cooled overclocking section, I chose to use a Thermalright XP-90 heatsink equipped with an 80mm Vantec Tornado fan. It's probably one of the better combos on the market right now in terms of cooling capability but there is a high price in terms of noise level. Boy those Tornados really do sound like a hair dryer!

Starting at 200 MHz I set the clock multiplier of the processor to 11x (or stock) and started to raise the motherboard clock frequency slowly. It didn't get too far before the processor started to flake out at a low 217 MHz (2.39 GHz). I began to experience some weird BSODs while loading Windows or running SiSoft Sandra. Raising the CPU voltage to 1.55V fixed these issues and I continued pushing the processor higher.

I ran into problems at 233 MHz (2.56 GHz) once more; this time the system would load Windows but when running any benchmarks it would lock up or BSOD. Increasing the voltage was the key again, and this time it went up to around 1.65V. Our third problem hit at 237 MHz (2.61 GHz) and I had to increase the voltage slightly to 1.7V to get further.

With air cooling, the Athlon64 3500+ maxed out at 242 MHz (2.66 GHz). Anything higher and the processor was unstable at any chipset voltage. Temperatures were a bit high for my taste too; the DFI LANParty NF4 SLI-DR motherboard reported CPU temps as high as 55 degrees Celsius.