Ever since it became clear that DDR rather than RDRAM would fuel the Pentium 4’s future, the dual DDR chipset has been looked to as the true high performance concept that would provide the higher levels of bandwidth that the CPU needed to perform well.  Our first concrete example of how a dual DDR chipset would perform when mated with the Pentium 4 came with Intel’s release of their E7205 chipset, which proved that dual DDR 266 was capable of equaling or exceeding i850e performance across the board. 

 E7205, however, is not meant to be a mainstream dual-DDR solution, as Intel as positioned the board as a workstation platform and priced it accordingly.  This makes the board rather pricey, as we’ll discuss later.  The SiS 655 is a mainstream-focused dual DDR solution that will not only arrive at a much lower price point but supports the faster DDR 333 solution as well.  If it offers higher performance than the E7205 it may well take the crown as the fastest P4 solution available. 

 Intel and SiS have been playing leapfrog for that particular title since the release of last summer’s SiS 648.  The 648 was easily SiS’s best chipset to date and offered excellent performance for its cost, but was narrowly surpassed by Intel’s i845PE which came several months later and added Hyper-Threading support (which the SiS 648 lacked).  SiS has used their Pentium 4 line of chipsets to break their former reputation as a budget-chipset provider and establish themselves as a major player in the high-end P4 market.  Both the 648 and the 645 before it were steps in this direction?we’ll see if the 655 can sustain the push or not.

 The SiS 655 Chipset:

 The 655 is very similar to the earlier 648 and uses the same southbridge as the earlier design. SiS uses their patented MuTIOL bus system to provide the 655 with 1 GB /s of bandwidth, which ensures that even a system making extensive use of the 655’s integrated FireWire, onboard Ethernet, and USB 2.0 features will not be bottlenecked.  The major new addition to the design is, of course, dual DDR support.

 Dual DDR at 333 MHz actually gives the 655 more bandwidth than the CPU is able to effectively use, marking the first time since the launch of the P4 that the system’s available DDR bandwidth has been greater than the potential bandwidth capability of the CPU.   There is one feature missing, or at least not enabled, on the SiS 655 chipset?a switch for Intel’s Hyper Threading capability is nowhere in sight.

 The Hyper-Threading Question:  Does the SiS 655 Support It?.or Not?

  Although SiS does now hold a license for Hyper Threading technology, there is no option on the AX45-4D MAX to enable it.  We’ve contacted AOpen for more information on the situation.  There is a difference between having a license for a technology and being able to execute it successfully; its possible the SiS 655 chipset was already fully designed before SiS acquired its license. 

 Benchmarks shown on the SiS 655 chipset today are with Hyper Threading disabled, for that reason.  All tests run on the Intel boards were run when Hyper Threading enabled.  Although this does result in a configuration fluctuation, we feel the end comparison is representative?machines with Intel chipsets are likely to ship with HT on, machines that do not support it obviously will ship with it off.

 Now that we’ve discussed the SiS 655’s general features, additions, and limitations, let’s examine the AOpen AX45-4D MAX itself. 

next > next > next >

---

• Board Layout (0 of 3)
• Board Performance (0 of 3)
• Conclusion (0 of 3)