Overclocking my 9950 BE Need advice

Ya your gonna want 200mhz x 15 = 3ghz. If it boots up stable and passes torture testing, you won't need any extra voltage. If it doesn't do either of those, add a little voltage, generally I like to add +.05V. If its stable like that, leave it. If not, continue adding voltage until it is.
Also, you need to make sure your temps are in check. I wouldn't let that CPU go much past 55C, 65C is the highest I would let it go.

Use prime95 for stress testing. Stress at least an hour. Ocers typically burn for 6+ hours. Use small fft.
http://files.extremeoverclocking.com/file.php?f=103

Monitor temperature:
http://www.alcpu.com/CoreTemp/

First of all, all hardware is different and of varying quality, just because someone gets a certain OC does not mean you can get the same, you may get worse or even better, That Said.

I'm using aftermarket CPU air cooling, a Zalman CNPS9700 LED.

Vista Home Premium 64

Its very important to MANUALLY set your memory voltage and timings, to whatever they should be!

Presently I'm running a 16x multiplier @ 1.4250v Vcore, however I'm also running a highly modified case with excellent airflow, my GPUs are separated from the CPU section.

The GPUs do not contribute heat to the CPU section, and that makes a serious cooling difference!

Case Airflow is very important, as to what you can attain on an airflow setup!

Here are my specs:
AMD Q9950BE
ASUS Crosshair II Formula M/B
Corsair Dominator TWIN2X4096-8500C5D 4G = 2 x 2G
BFG 8800GT Bios Flashed to 726/1819/1003 2 in SLI
Creative Extreme Gamer Fatal1ty Pro
Seagate 500G SATAII

Here are my M/B BIOS settings [Caution: Doesn't mean you can use the same, this is shared, Use At Your Own Risk Actual Settings]
9950BE OCd to 3.2G idles @ 41c
Overclock Features set to > Manual
CPU Freq > 200
CPU Multi > 16X
K8 NB HT Speed > 2Ghz
K8 NB HT Width > 16 16
Pci-E Clock > 100
CPU-NB Multi > 10X
Vcore > 1.4250v
DDR2 Voltage > 2.100v

DRAM Configuration for Corsair Dominator
Memory Clock Frequency > DDR2 1066
Tcl > 5
Trcd > 5
Trp > 5
Tras > 15
1T/2T > 2T
Gang > Enabled
Remap > Enabled
Skew > Auto

CPU-Z is reporting Core VID as 1.250v that is a CPU-Z error, the Core VID is actually 1.4250v

Hope this helps someone! Ryan