Can someone help me with my memory timings????

Hello guys

This is my PC config:

AMD Athlon64 3000+
Asus K8V-X Motherboard (VIA K8T800 chipset)
Kingmax 'Hardcore' DDR500 Memory (1GB)
NVIDIA GeForce FX 5900

Since my motherboard is not designed for overclocking I cant find a way to make my RAM run at 250MHz (DDR500) unless I raise the FSB clock. Would it be safe to do that?

Also, the SPD timings for my RAM are 3-5-5-10 (CAS Latency-RAS to CAS Delay-RAS Precharge-Cycle Time aka TRAS)

What would be the ideal timings for a DDR400 setup in case I'm unable to get it running at DDR500?

Thanks for your help

Regards,
Firecat