Been trying for months to overclock using the guides on this forum

[Rainyn]

I'd say your CPU-NB is too low, try upping it to 2400/2600, together with the HT link. IIRC, Thuban's like to have CPU-NB and HT link running at the same frequency...

And set the CPU-NB voltage to 1.2v/1.25v.

EDIT: have you read this guide? There is about everything you need to know regarding Phenom's overclocking...
http://www.overclockers.com/forums/showthread.php?t=596023&highlight=dolk's+guide

I've read his entire guide from beginning to end at least once, and I've studied the last section on overclocking Thubans. Part of my strategy was trying what you suggested - I've tried everything I could think of, including the very settings you suggest. To be fair I dialed them in again and tried rendering an image on all cores. It was doing fine for nearly 15 minutes and then crashed with just seconds to being done rendering. Prime95 crashed within 60 seconds of starting (not the torture test this time).

I've attached a couple screenshots representative of several I took during this process. Also, note the activity graph in the core temp wigit. I've seen the processor do this in the past (flatline) but I don't know what causes it. These two screenshots were taken roughly 10 minutes into the render.

 

[Rainyn]

Got it! (sort of)

A big huge DANG - I was in the middle of writing this post, 30 minutes into Prime95, when I went to upload this super awesome screenshot and the PC bluescreened when I hit upload.

Meh - no idea if it was something to do with the network or my PC just decided to take one huge dump all over my most triumphant post. I probably should have turned Prime95 off before I began the post. Oh well.

But the good news is I finally got 4Ghz (semi?) stable.
Here's a list of what I changed in the BIOS and my excellent screenshot:

CPU Freq Mult - 20
CPU volt - 1.4375
NB Freq Mult - x14 (2800 Mhz)
CPU NB Volt - 1.2875
HT Bus Speed - 2200
DRAM Volt - 1.55

I had gotten the PC semi stable on the RAM I've had in since I started this thread. But I switched it out on a whim for my other 2 sticks of 2GB RAM modules and that is when the PC became much more stable. Interestingly, the first two were "Made in the USA" and the stable ones - from China - D'oh!

I read this post from start to finish, which is what ultimately helped me put the last few puzzle pieces together.
(full-size of desktop image here)