KrispySausage writes "One of the big features discussed in early speculation of Windows Vista SP1 was the kernel upgrade, which was supposed to bring the operating system into line with the Longhorn kernel used in Windows Server 2008. With Vista SP1 going RTM, there hasn't been so much as a peep from Microsoft about the mooted kernel update. Has it happened? Well the answer is yes it has. Presumably the main reason for Microsoft's silence on the subject is that as they're keen to promote the improvements and enhancements to Vista, rather than placing emphasis on a kernel upgrade, which some people might see as a risk of newly-introduced instability."