4 dimms of gold vx?!?!? Man that stuff runs with errors right out of the box. You got to burn that sh!t in for a few days or it will give you thousands of errors at that voltage. Try 200fsb w/ 3.4 volts for 2-3 days running memtest. That will burn them in nice and good. After that you can bump up fsb untill you get more errors, and then you repeat the burn in period at a higher fsb, say 240 fsb, until you reach your max.
Running 4 dimms is not good for A64 mem controller! You just bought yourself a headache. With that crazy ram, you won't know if its the memory or the mem controller that giving you errors. I would burn-in the dimms in pairs. After, you can put all four in and see how high you can get.
You might have been better off with some TCCD. At least with TCCD you can run right out of the box, without burn in and active cooling. But hey, VX has the possibilty of running faster, but not without lots of tweaking, extra heat and noise. Good luck!