Overclocking Asus P5K-VM Motherboard

It would help to know what CPU and RAM you have installed. At first glance it appears you have only one RAM speed, DDR2 1066 so that memory booster may help. Your board manual may be of assistance.
I wouldn't expect much from ASUS support.

werty12345,
My advice would be to add more ram and even though you won't net the full 4 gigs that's what I'd add as long as they are matching sticks. Then if you can't find them then consider two or four new matching sticks of the highest speed that ASUS shows tested and approved for your board. You can also get a little kick in the stock ram boot by adding a usb stick or flash card and commit it to readyboost.

Definitely get more RAM, with one stick you only in single channel mode. As linne said, get a matched set and install it, PC2 1066.

wert12345,
I'll have to differ to a Intel overclocker and likely someone with some Asus hands on knowledge. My only suggestion is that overclocking has such a small and mostly unnoticeable increase, but compared to doubling ram or replacing with higher speed ram the differences are Night & Day. If cost is an issue then pull out all your usb drives and find one fast enough with at least 4-8 gb of space and set it up for ready boost and let the system place needed files on it over a week or two and even that has a performance gain. I find that my drive to OC has little to do with actual/noticeable performance gain......how sad !

That's true, those of us who over clock see no real world performance boost. It changes your WEI and gets higher benchmark numbers and you can brag.

Installing the most and fastest RAM you board will support will help out though, especially since you apparently have one RAM module installed.

I've no found Ready Boost to help me out, but YMMV on that. IT acts more like a cache than RAM and there are no USB drive that run nearly as fast as RAM.

Correct but in my pre ssd days I have to say that dedicating a full 8gb stick and leaving it for a week and I for sure noticed it when it was removed. In 10 10ths I would give it a 2, with extreme OC around 3-4 max and wicked matched ram more like 6-7ths.