Summing up I would like to say that no definite conclusion can be made about the new i925/i915 platform so far. Of course, the new chipsets feature a number of indisputable advantages, such as High Definition Audio support, Matrix RAID technology and WiFi. Also among the highs of the new i925/i915 solutions I could mention the new PCI Express x1 bus, which should eliminate all bandwidth limitations imposed by the 33MHz 32bit PCI bus upon some devices.
Among the new features of the reviewed platforms are a few arguable issues, too. Among these we should certainly mention the PCI Express x16 bus for graphics cards, which has no alternative and offers the users no choice. Of course, higher bandwidth of this bus is a true plus, but contemporary graphics cards can still be quite happy with the good old AGP 8x. Anyway, the progress keeps going and the graphics cards are very likely to learn to use all the advantages of the new PCI Express x16 in the future. I am only upset that the new chipsets are incompatible with the widely spread cool AGP 8x graphics solutions available in the today’s market.
A definite drawback of the new i925/i915 chipsets is DDR2 SDRAM support. So far this memory with high bandwidth and higher latency than that of DDR400 SDRAM cannot guarantee the new platforms any performance gain at all. In fact, DDR2 support is a serious slow-down for i925/i915, so that these chipsets show pretty low performance compared with their predecessors. I will not deny that DDR2 SDRAM is a promising solution for the future. Of course, later on when the processor bus speeds up and the DDR2 memory specs get improved and polished off, this memory type will become truly demanded. But today using DDr2 memory in Pentium 4 platform doesn’t make much sense.
The graph below shows how greatly the performance drops when we move from i875P to i925X Express in systems with Pentium 4 (Prescott) and Pentium 4 Extreme Edition (the CPUs work at the same frequency).
i925X owes these dramatic results to the DDR2 memory in the first place. Luckily, i915 Express chipset family targeted for the mainstream systems is backward compatible with the DDR400 SDRAM. Hopefully, this fact allows i915 to compete successfully with i865. However, we still have to check if our expectations are justified.
At the same time I would like to point out that Prescott processor cores work with the new chipset much better than Pentium 4 XE based on the Northwood/Gallatin core. Of course, DDR2 SDRAM looks better when there are CPUs on the latest cores involved, as they feature enhanced data prefetch algorithms.
Together with the new chipsets Intel also introduced a new processor socket form-factor: LGA775. On the one hand, this transition allows Intel to keep increasing the clock frequencies of its processors as well as that of the system bus without ay concerns, while on the other hand it means that the new CPUs will not be compatible with the old mainboards, as well as the old CPUs will not be able to run in the new mainboards.
All in all I have to say that such a great lot of innovations Intel introduced in its new i925/i915 chipsets deprive the users of the upgrade opportunities completely. In particular, when the users will go from the old platforms to the new ones, they will have to replace not only the mainboard and the CPU, but also the graphics card and the memory. Besides in many cases the shift to i925/i915 platform will also require new hard disk drives with SerialATA interface and some users may also need to replace a few peripherals with their PCI Express x1 analogies. This way, the launching of the new i925/i915 solutions is not just a technological breakthrough but also a perfect way of getting more money from the users.
Therefore we observe quite a paradox. Having upgraded the platform and added a lot of innovations, some of which are really handy, Intel at the same time pushes users to replace their CPUs, memory and graphics cards, even though replacing all this equipment will hardly have any positive effect in the long run. I believe that there are hardly that many arguments in favor of the new platform this way. Especially since Intel is going to release new CPUs with faster bus, larger L2 cache and 64bit extensions in the nearest future. When this happens maybe i925/i915 platform will start looking more attractive to us. And in the meanwhile the good old i875/i865 solutions, which have already stood the test of time, are perfectly suitable for our systems. The time for i925/i915 hasn’t come yet.