.09 Athlon 64: Value, Speed and Overclocking

Overclocking Results and Heat

One of the most pressing questions that many are asking about the new 90nm processors is how they overclock. Will the die-shrink deliver the kind of headroom seen on the Intel Northwood chips when they were first introduced? Our first tests with the 90nm 3500+ were quite good, so we bought a 90nm 3000+ to see if results were comparable.

Front Side Bus Overclocking Testbed
	90nm A64 3500+	90nm A64 3000+
Processor:	2.2GHz 512k L2 Cache	1.8Hz 512k L2 Cache
CPU Voltage:	Default (1.4V)	+8.3% (1.52V)
Cooling:	Thermaltake Silent Boost K8 Heatsink/Fan	Thermaltake Silent Boost K8 Heatsink/Fan
Power Supply:	OCZ PowerStream 520	OCZ PowerStream 520
Memory Timings:	2.5-4-4-10 1T	2.5-4-4-10 1T
Memory Voltage:	2.75V	2.8V
Maximum OC:	2610 (+18.6%) 290x9	2610MHz (+45%) 290x9

As you can see, the 3500+ and the 3000+ both topped out at about 2.6GHz (anticipated FX55 speed) with default or modestly increased CPU voltage and air cooling. This is a decent overclock of about 20% on the 3500+, but the 3000+ reached the same 2.6GHz overclock from a much lower stock speed of 1.8GHz. This means that the new 90nm 3000+ overclocked an outstanding 45% with modest increases in CPU voltage.

The only real difference in overclocking the 3500+ and 3000+ in our tests was that the 3000+ required a little more CPU voltage and memory voltage to reach the same overclocks achieved with the 3500+. This 45% overclock is exciting, and it gives us reason to expect even better headroom possibilities when AMD gets the 90nm process tweaked. Since these two 90nm parts came from different sources and were purchased from dealers, we feel comfortable that they are representative of the 90nm chips available in the market. Overclocking results are never guaranteed, but these first results with AMD 90nm processors are full of promise. If the 90nm 3000+ performs this well in larger samples, it will become the darling of the Enthusiast community.

All Performance benchmarks were repeated at the highest overclock that we could achieve - 290x9.

The Overclocked Performance results are included in the Performance Comparison charts to show the performance headroom found with the new 90nm chips. For better comparison, results are also included for the fastest processors currently available from AMD (FX53) and Intel (560 - 3.6GHz).

Thermal Performance

AMD claims that their 90nm process generates less heat than the 130nm process and requires lower wattages. Of course, the heat that is generated is concentrated in a much smaller area than the larger 130nm die. We will not likely know the true impact of the 90nm shrink on heat dissipation until AMD produces their fastest CPUs in 90nm, so we decided not to run comprehensive heat tests until the faster processors were available in 90nm.

We did check reported temperatures in the BIOS to get an idea of the temperature trends with the new 90nm process. At the same stock speeds, the 90nm and 130nm chips were showing the same CPU temperatures. There was neither improvement from the 90nm nor any indication of running hotter. Overclocked to 290x9, the 90nm parts were 1 to 5 degrees Celsius cooler than a 130nm FX53 chip clocked to the same 290x9. These results are not the objective tests that we will run on high-speed 90nm parts, but they confirmed that the AMD 90nm process appears to run at least as cool as current 130nm processors.