Conroe vs. AM2: Memory & Performance

2.93GHz with DDR2-1067 Performance Comparison

It is clear enough that despite the poorer memory bandwidth, Core 2 Duo is the performance leader by a substantial margin at stock speeds. You have seen that in all of the results posted in this article. This conclusion will not satisfy all our readers, however. Many have theorized every incarnation of performance imaginable with AM2 having higher clock speed, higher bandwidth, or higher speed memory than it currently does.

To best answer these questions we put together the fairest comparison we could think of to directly compare Core 2 Duo and AMD AM2. This consists of running both processors at the exact same speed - 2.93GHz - achieved at the same ratios - 11x266. This involves overclocking the AM2 FX62 to 2.93GHz and raising the "bus" speed to 266. That allows an 11x266 ratio to match Core 2 Duo. The desirable side effect is that while AM2 does not really support DDR2-1067, by setting the memory to DDR2-800 we reach DDR2-1067 speed at the 266 speed setting. While this slightly stacks the deck in AMD's favor, it is as close as it is possible to get at running the two systems at the same speed, same memory timings, same memory voltages, same memory, and same video card. We are comparing two identically configured systems with AM2 powering one system and Core 2 Duo powering the other system.

Results are particularly interesting in that the fastest current AM2 processor, the FX62, is overclocked about 5% in CPU speed and 33% in "bus" speed over a stock AM2 system.


Frankly the gap that remains in Super Pi results when comparing AM2 and Core 2 Duo at the same speed was something of a shock. Clock for clock, with all other variables the same, Core 2 Duo is still almost 60% faster than AM2. There is nothing complex about calculating the value of Pi to 2 million places, but it does show the true power of Conroe in computation-intensive tasks.



Despite the improvements Intel has made in intelligent read-ahead for memory, AM2 still has a huge lead in buffered memory bandwidth. This is a result of the superior on-processor memory controller used on AM2. The results become much closer in Unbuffered memory results, which is normally more revealing of performance in real-world applications, but AM2 still has a wider memory bandwidth. The unfortunate reality is AM2 is not starved for memory bandwidth and cannot really make effective use of this advantage. AMD clearly knows how to deliver memory bandwidth, so the task now becomes to modify their core logic to make better use of this advantage.




We can now say with authority that Core 2 Duo is the faster performer clock-for-clock across the board. At the same 2.93GHz Far Cry is 27.7% faster, Half-Life 2: Lost Coast is 12.4% faster, and Quake 4 is 22.2% faster on Core 2 Duo. Of course AMD does not currently have a 2.93GHz CPU, so we tested by overclocking FX62. This suggests that FX64, or whatever it will be called, will not help much at 3.0GHz with a 200 clock speed.