the thing is that my computer is pretty stable at 433@433, but when i put it to 433@488 it gets me lock ons during high load...i have replaced EC10, an it got me some stability now...been running UD agent whole night, and it didn't lock...
so my next quest is to make it work on 75MHz FSB...to do that i must replace my Q6 with something better...but here is the problem, it's not standard issue VRM and i cant find it in Croatia...to ship it from US, maybe...but what firm will do that?
so i'm back at the begining...trying to find a problem fixer for me!
that is why i send you that file...in there is a list of parts from local store, so you might suggest me sthg... (at all i'm just a mechanical engineer, and don't know so much about electronics!)
Digikey will ship to you (I noticed that your location was Croatia after I posted yesterday and went and looked), but you'll pay through the nose on shipping (it looked like the minimum for shipping and handling was US$18, probably not worth it).
Anyway, it might be the processors. They aren't all capable of hitting 600MHz, and the lower the labeled clock speed, the more likely they don't. Intel left a lot of headroom on the celeron1s, but the only gauranteed speed is the packaged speed.
You might try pulling your PCI cards and play with it that way, see if any of them are causing problems. PCI cards are notorious for being picky about their bus speed (which should be 33MHz), and when you aren't running the BP6 at 66, 100 or 133, the PCI bus is overclocked. This may be causing cards to be flaky, but it's just a possibility (and I might be wrong on this, I tend to stick to frequencies which keep the PCI bus clocked correctly).
If you really want to get a new Q6, the specs are that it needs to be a "low dropout" adjustible 3 terminal voltage regulator. The reference voltage needs to be 1.25V (pretty standard, but check spec sheets anyway). If you need to find the datasheets, I find that google or yahoo work pretty well if you do a search on the part # and the word "datasheet". (I can't read your parts list, I don't have any software that reads excel files.)
Anyway, I would play with hardware configurations, recap the board, and then try modding the voltage regulators. Before that, though, I would also get some hardware monitoring software, and actually watch Vtt while you put the board under load. Watch to see how much it actually droops. See if it might actually be the problem. Throwing an LM317 in mine didn't actually stop Vtt from drooping significantly on my board.
 133MHz is not normally attainable. I've heard reports of it working on new BP6's configured with a single processor, but that's it. It would also require some pretty hardcore cooling (Peltier) to keep the BX440 from frying itself.
In other words, yes, I've almost given up on 133MHz FSB... Almost