Waiting For Santa, Continued
The second player in this new arena was ALi with its MaGiK1 chipset. Similar to AMD's 760 in terms of specs, it supports the new processor bus clock as well as DDR-SDRAM. We refrained from reviewing platforms with this chipset so far, because the performance we saw was hardly worth talking about. Motherboards with ALi's MaGiK1 chipset are finally becoming available these days and the product has matured a bit, so that we decided to include MaGiK1 in this review.
Since its impressive success in 1999 and 2000, VIA was expected to be one of the first chipset makers to provide a platform for the 133 MHz-FSB Athlon. It's commitment for DDR-SDRAM generated big hopes that this new chipset would come with DDR-support. Unfortunately it turned out that neither of those hopes would come true. VIA was the last of the three that came up with a chipset that supports the 'Athlon C' and this chipset does still not provide DDR-support. In fact, the Apollo KT133A is simply a minimally changed version of VIA's well-known Apollo KT133 chipset that is now certified to run the processor bus at 133 MHz reliably. I will have to disappoint those of you, who might expect that KT133A-motherboards would become available very soon, because it seems as if a missing design spec from AMD will force most motherboard makers to redesign their KT133A motherboards. My information says that none of those boards was designed to support a maximal processor current of 46 A for Athlon processors at beyond 1500 MHz, because AMD supplied this spec too late.
SDR-SDRAM Vs. DDR-SDRAM
Theoretically DDR-SDRAM provides double the bandwidth of normal SDRAM. At 100 MHz memory clock it's able to supply a data bandwidth of 1600 MB/s, at 133 MHz it goes up to 2100 MB/s. That is why 'Team DDR' decided to call the specs of those two DDR-memory types 'PC1600' and 'PC2100'. However, I have to disappoint you, if you should think that DDR-SDRAM is simply twice as fast as SDRAM at single data rate. The basic reason is rather simple. While DDR-SDRAM is indeed able to provide double the peak bandwidth of normal SDRAM, it has still the same (CL2 DDR-SDRAM) or even a slightly worse latency (CL 2.5 DDR-SDRAM) than its older sibling. The result is that in worst-case situations DDR-SDRAM can be as slow or even slightly slower than normal SDRAM. At the same time DDR-SDRAM can easily outperform single data rate SDRAM under ideal conditions. In average, systems with DDR-SDRAM are most certainly faster than systems with normal SDRAM, but the gain depends on the application and can hardly ever reach more than 20%.
We have provided an article with more information about DDR-SDRAM a few months ago and you will also find a very interesting technical write-up about the memory situation at Kyle Bennett's HardOCP .