MSI K8N SLI Platinum O/C issues

[A_X]

I'm trying to overclock my Athlon64 3200+, but I need some help because I seem to be stuck...

My rig:

MSI K8N SLI Platinum
AMD Athlon 64 3200+ 0436MPM
2 x 512 MB PC 4400 G.Skill
2 x 250GB Hitachi 7K250 S-ATA 8 MB @ Raid0
Matrox Millennium II PCI videokaart (wating for X850XT)
NEC ND-3500 dual layer dvd-brander
Onboard soundblast en gigabit nic
TruePower 380 Watt ATX

I got my SLI Platinum yesterday and started to try to overclock my 3200+ on it, but I encounterd some problems. I tried to overclock in in the following manner:

1. Try to obtain the max speed of the CPU.

First I set my mem to the standard timings of 2.5-3-3-7-1T and chose a large mem divider to make sure that my memory is not going to be the bottleneck. Next I increased the Vcore and started up the HTT in small steps of 2/3 mhz at a time to check how high it would go. To my astonishment the max HTT at which it would boot was 225Mhz (10X225, which is 2250Mhz). Everything under a HTT of 225 is rock stable, but anything over it doesn't even allow the board to boot...


10x224Mhz (clickable screenshot)

2. Decrease the multiplier, increase the HTT and mem divider set to 1:1

So I thought I just had a bad CPU, but since my mem is garuanteed to run at 275Mhz 2.5-3-3-7-1T by G.Skill, can't I just decrease the multiplier and increase the HTT with the mem divider set to 1:1?
So I set the muliplier to 9x and the mem divider to 1:1 and again gently started to increase the HTT by steps of 2/3 mhz, but now I still got stuck at around 225 HTT.... (9x225= 2025Mhz) . I tried numerous Vcore and DDR voltages and also tried to set the HT multiplier to 4 and 5, but nothing seems to help. Again anything over a HTT of around 225 doesnt allow the system to boot and everything under is rock stable.


9x225Mhz (clickable screenshot)

Something weird that I noticed is that when I overclock it with Clockgen I can get it to do Pifast and Prime to around 2500Mhz. So the cpu doesn't seem to be the bottleneck. The PCI/SATA also seems to be working fine (according to Clockgen).

Another thing that seems equally as weird to me is that MSI Corecenter and the H/W Monitor in the bios always say that my Vcore is 0.10V to 0.15V lower then I set it to... Like in the screenshots shown above the Vcore is set to 1.67V, but Corecenter (and bios) say that it's running on 1.55V... The other rails are also showing a little bit of undervolting. Could my PSU perhaps be the cause of it not wanting to boot over a certain HTT? The Antec Truepower 380W is a pretty good PSU and besides I don't have a really heavy loaded system. Especially since my X850XT hasn't arrived yet and I'm using a cheap PCI videocard from 1997.

Can anybody perhaps give me me some advise on this because I'm lost... (or am I missing something?)