April 1999 SDRAM Comparison

This month AnandTech makes another addition to the SDRAM test bed setup, using the latest beta PC133 modules from none other than the previous crowned champion, Samsung. Since the original review was published last month, the availability of the PC133 modules has not increased at all, however Enhanced Memory Systems' HSDRAM has finally hit the market and is available for sale. At $135 for a 64MB module, EMS has safely placed their SDRAM within the reach of only those that truly want to say that they have the most stable SDRAM available on the market.

Something only a small portion of the population will take into account is that the 133MHz FSB frequency is not a realistic goal for anyone that plans on using an AGP accelerator with any current Slot-1 motherboard. The reason? All currently available Slot-1 chipsets, including those from VIA/SiS, only allow for two possible ratios for the AGP clock frequency, those two being a 1:1 ratio with the system's FSB frequency, and a 2:3 ratio. Even when using the 2:3 ratio, the AGP frequency, at the 133MHz FSB, ends up at around 88MHz, or 33% over the specification for all AGP cards (66MHz).

Users have also provided the argument that purchasing SDRAM that is capable of running at 133MHz now would save another costly memory upgrade later this year when Intel officially introduces the 133MHz FSB specification with their upcoming Coppermine CPU. Unfortunately this approach is not too incredibly sound either, as there is no indication as to whether or not the Camino chipset (the first 133MHz FSB chipset from Intel) will even support today's SDRAM modules. The final decision boils down to how cheap and in what quantities Intel's preferred Rambus DRAM (RDRAM) modules are available in closer to the launch of the Camino. In the absolute worst case scenario, if the popularity of RDRAM is not as great as they are predicting it to be, Intel may be forced to adapt the PC133 SDRAM standard VIA has been pushing the industry towards. Although VIA will be shipping boards based on their 133MHz FSB capable Slot-1 chipset, the Apollo Pro 133 Plus, in June/July, owners of older PC100 SDRAM should rest assured as the chipset will most likely allow for asynchronous or pseudo-synchronous operation of the memory clock, an "extremely-VIA" feature that has been around since the introduction of the first Super7 motherboards.

With that said, it is time to take a look at how the PC100 champ stacks up to the rest of the competition when armed with a new, albeit pre-release, set of PC133 compliant SDRAM chips and a familiar looking PCB.

Preparing the Test

In order to isolate the memory modules as the only realistic causes of any fluctuation in stability, choosing the proper test bed was a bit of an ordeal, luckily AnandTech was aided in lab by the wonderful folks over at Kryotech who supplied AnandTech with a room temperature cooling system a week before the first stability tests were to commence. At the heart of AnandTech's SDRAM stability test bed was a Pentium II 333, capable of being reliably overclocked to 416MHz, running at room temperature with the aid of Kryotech's Renegade ATX-PE Room Temperature Cooler. The ambient case temperature of the Renegade test bed was kept at room temperature, or approximately 22 degrees Celsius, as was the surface temperature of the Pentium II processor.

The 333MHz Pentium II was chosen for its versatility in terms of clock multiplier support, as AnandTech's sample remained clock unlocked, and allowed for the usage of the 2.5x clock multiplier when testing higher FSB settings. In order to gain support for a wide variety of FSB frequencies, two motherboards were used as the basis for the test bed, the choice to use two motherboards came to make sure that there were no specific incompatibilities between the SDRAM being compared and a particular motherboard.

The entire test bed was configured as follows: