Put rather simply, there are good reasons why those settings were the way they were before someone decided to go messing with them.
The page file is only really used when there isn't sufficient RAM, and disabling it could lead to problems down the road.
The second tip seems rather pointless. The Windows kernel is always in memory. Any modern operating system does this already. This is the central nervous system of the entire operating system, you always want to have ready access to it. Some operating systems, like Linux, will let programs preempt the kernel which can improve latency times, but the kernel is ALWAYS going to be in memory.
The third tip... Disk cache is horrendously slow no matter what you do. You're not going to see any worthwhile gain from messing around with disk caches. You'd be better off loading your system up with RAM so that the disk is needed less and less. And on that note, there's still a lot of outdated information floating about regarding how more than 512MB of RAM can slow your system down because it can't be properly cached. Unless we're talking about an original Pentium class system, this information doesn't apply. It was also based on a misunderstanding of the technical details. Uncached RAM is still going to be many hundreds of times faster than the alternative of using a swap/page file. By slower, it means that it might take a few extra nanoseconds for the computer to find the information it wants.
There's really little to be gained by any of these tweaks. You'd be far better off getting a faster CPU, more RAM, and a faster video card if you want to improve game performance. Most of the remaining performance bottlenecks have to do with the transport methods for getting data from one part of the computer to the other. Going from the hard drive to RAM, or vise versa, is the slowest link in the chain by far. You can't do anything about it, it's a hard coded limit. Next up is the RAM, which usually communicates at about a quarter the speed of the CPU. You can tinker with this on some systems, but it often leads to system instability.
The long and short of it is this: Any person or site that claims to offer significant gaming performance improvements via seemingly simple little alterations is most likely full of it, or vastly overstating the gains you'll experience. There is simply no software substitute for not having the proper hardware.
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic