X-bit labs

Contemporary Socket A Chipsets: NVIDIA nForce2 Ultra 400, NVIDIA nForce2 400, SiS748 and VIA KT600 (page 3)

Category: Chipsets

by Ilya Gavrichenkov

[ 07/08/2003 | 01:26 PM ]

Closer Look: NVIDIA nForce2 400

Watching vain attempts of VIA and SiS to develop a high-performance single-channel chipset for Socket A platform, NVIDIA decided to go on and not very long ago the company introduced one more solution: NVIDIA nForce2 400. in fact, this is the same NVIDIA nForce2 Ultra 400, but featuring only one memory channel. In other words, NVIDIA decided to move from the high-end chipset segment and get some presence in the mainstream as well by offering a solution for mainboards priced around $70-$100. Besides, this way the company could also find an application for the defective NVIDIA nForce2 Ultra 400 chips, which had only one memory channel working properly: they simply disabled one memory channel in such chips and then they were sold under NVIDIA nForce2 400 name.

Today there are hardly any NVIDIA nForce2 400 based mainboards in the market: the mainboard guys are waiting for the VIA KT600 and SiS768 to come, so that they could choose the most profitable solution out of these three single-channel chipsets. However, I would like to point out on my part that NVIDIA nForce2 400 is really good choice. If we disregard the absence of SerialATA support, which is definitely a big drawback for this product, we have to admit that the memory controller of NVIDIA nForce2 400 is very successful, even though it is a single-channel one. Even when we reviewed the very first nForce version we stressed that the major trump of NVIDIA chipsets is not the dual-channel design, but the DASP unit (Dynamic Adaptive Speculative Pre-Processor). The second version of this DASP unit has been implemented in NVIDIA nForce2 400 (just like in NVIDIA nForce2 Ultra 400).

As you know, this block is theoretically like an additional buffer (or cache, if you like it more), which is built into the chipset North Bridge. This buffer receives data, which should be demanded by the CPU later, according to the logical part of the DASP. This way, the DASP unit can use the memory bus more efficiently and reduce the memory latencies quite tangibly on data addressing in case of successful predictions and appropriate data prefetch. It is exactly this particular data prefetch mechanism of the NVIDIA nForce2 400 memory controller that NVIDIA pins its hopes on in competition with VIA. A little later in this review we will see that DASP proved absolutely up to our expectations in NVIDIA nForce2 400 making this core logic extremely attractive from the price-to-performance ratio point of view.

Soltek SL-NV400-64: one of the first mainboards
on NVIDIA nForce2 400.
Note that there are only two DIMM slots onboard.