The X38 chipset has definitely turned out to be less than we had initially hoped for, and with all the hype saying it would be the next big chipset without overclocking boundaries that are put into some chipsets to limit their overclocking potential, X38 has flopped out with higher power requirements and heat generation causing some overclocking problems; this is especially the case when it came to the memory side of things. If the Northbridge gets to hot it just can't handle the bus speeds.
X48 is Intel's big push to keep X38 alive while giving it a different name so it goes up a class, this by simply hand picking a set of chipsets that are guaranteed to work better.
MSI's first X48 to cross our labs really has us wanting more X48s to tinker with. If this is the result of simply selecting the best chipsets from the wafer, then Intel's getting things well sorted right now and we may even see better X38 boards if the chipset continues now that X48 is out.
Overall, the X48 Platinum packs in as many features as most other boards have along with the additional two PCI Express x16 slots for a grand total of four. We are seeing the beginnings of boards that totally dominate for graphics cards.