Best DDR400 Modules
Thus, our test session showed that the best memory modules could function at 400MHz frequency with 2-3-3-5 timings. In this case, the system working with 400MHz bus proved about 3%-7% faster than the system working with DDR333 memory and 333MHz bus. Ordinary DDR400 doesn’t allow setting CAS Latency = 2 at 400MHz and thus brings no such performance gain. So, below we discuss those modules that provided the maximum performance in our benchmarks.
First of all, we would like to single out OCZ EL DDR PC-3700 Enhanced Latency modules.
Theoretically, these modules can be clocked at 466MHz. So, it is no wonder they do excellently at 400MHz. But, according to the official specification, it’s recommended that you set CAS Latency = 2.5 and raise memory voltage to 2.7V for these modules to work at 466MHz. As for 400MHz, they worked without any problems with 2-3-3-5 timings.
We also tried to find the maximum frequency these modules could work at in our testbed with 2-3-3-7 timings and 2.6V voltage. We got 456MHz and it’s the absolutely best result among all memory modules we took for this review.
CMX256A-3500C2 modules from Corsair are second best.
The manufacturer claims these modules can work in mainboards based on VIA KT400 chipset at 434MHz frequency and with 2-3-3-7 timings. In our nForce2 based system they worked stable at 400MHz with 2-3-3-5 timings, just like OCZ EL DDR PC-3700. During overclocking with 2.6V voltage and 2-3-3-7 timings, Corsair CMX256A-3500C2 notched 440MHz.
Many memory makers have started to sell modules in pairs especially for dual-channel chipsets. Such modules are specifically tested for collaborative work. We checked out one such pair: OCZ EL DDR PC-3500 Dual Channel Enhanced Latency Series.
These modules also did well at 400MHz with 2-3-3-5 timings. Their specs say they can work at 434MHz with CAS Latency = 2. And these 434MHz are exactly what we got overclocking these modules at 2.6V voltage and with 2-3-3-7 timings. By the way, OCZ uses copper heatsinks on its modules and permits setting up to 2.8V voltage on memory chips. Of course, the overclocking results would be even higher in this case.
Among brand memory modules, Corsair CMX256A-3200C2 are immensely popular now.
And no wonder they are. These modules, just like their faster mates, could work at 400MHz with 2-3-3-5 timings. Further overclocking showed, however, that they don’t have a big “frequency reserve”. The maximum clock-rate they worked stable at with 2-3-3-7 timings and 2.6V voltage was 420MHz.
As our tests showed that memory timings seriously affect the performance, the use of high-quality memory becomes one more way to improve the performance of your system.
A year ago we showed that it made sense to overclock the Athlon XP system bus from 266 to 333MHz. It resulted in about 7-10% performance growth. In October, AMD used this possibility and rolled out processors intended for the 333MHz system bus.
Will the story repeat? We learned today that the transition of Athlon XP to the 400MHz bus also could increase their performance. This time, however, the performance growth is smaller, about 6-7% in some cases. Moreover, to get even this small growth, you have to use high-quality memory modules with pretty aggressive timings. Nonetheless, the shift to 400MHz bus is the easiest way available now to squeeze some extra speed out of the Athlon XP series.
The disadvantages of the 400MHz bus are obvious: older mainboards and chipsets have to be re-tested for stable and faultless work with it. Moreover, 400MHz-bus processors may have limited compatibility with older platforms and require new mainboards.
It’s hard to tell now, which way AMD will choose. But if you are in no mood to wait, do the transition yourself! You will need a mainboard capable of working at 200MHz FSB and high-quality DDR400 memory modules. You can look up our recommendations on the topic above. We would only like to add that not every DDR400 SDRAM is of help in the noble quest for raising Athlon XP system performance.