Power failure HTPC 200w DC-DC ??

After many empty web searches, it seems i have a very unique power failure issue in this HTPC rig :

i7 2600k
AsRock z68m-itxHT
8Gb G.skill 2133
HD6670 LP
OCZ Aglility 60GB
300GB WD Velociraptor 2.5"
Slim Blu Ray
2x 20cm UV CCFL
200w DC-DC 24-pin PSU - 203w X-box360 Brick (wired to 12v ON)
XSPC 450 Pump (RX120 - AlphaCool NeXXus HF)

The CPU used to do 4.5GHz all day for the first month after the brand new
build and ran smooth and consistent. I backed it off to 4GHz because that was ample. Now, at 3 months old, anything over 4.2GHz (with some load) will cause an immediated Power failure to the WD Storage and BR. Why ? Is the 200w PSU dying ? The lighting fades and flickers then re-surges. Only rarely will it freeze though. It seems the DC-DC unit will send any power it has left to keep the Cpu/Display and other vitals 'alive' and avoids crashing. I was suprised to even get the 4.7 considering the limited power. Watt meter peaked at 220w. Initial design was Pico160XT which failed to boot at stock.

When designing the build, I allowed for a full size ATX in place of the pump and rad and this PSU and cooling is only an experiment for summer (here in Australia), which explains the 'powerful' components.

Any advice or experiences would be appreciated.

I suspect the power brick is dying, those things have terrible cooling and overloading it isn't likely to help much.

The GPU is 63w before OCing. The CPU is ~75 before OC, probably 100-120 after OC.
Add in the rest of the various bits and the 220w from the wall seems pretty reasonable, and over the 203 the xbox brick is prepared to cough up.

If you're feeling brave take a multimeter to a Molex connector and see what the voltages look like under load at 4GHz. Yellow wire is 12V, red is 5V. They should be within 5%.

11.1v load and 11.56 idle. ??
4.95v all round on the red

I have kept a close eye, (and hand) on the power brick and it never gets suspiciously hot. Even after 10 hour runs which suggests the power runs straight through it. I have 3 bricks (203w) and this is the only one that runs it.

11.1 is well under spec, the brick isn't cutting the mustard.
That'd be the source of your issues.

That was it Bobnova ! Watt test (prime) 4 GHz max at 173w. Then again 168w. Intsant crash at 4.1 still drawing 168w. Thanks man.

Brand New brick arrived and rather than kill this one, I'm going to back off to 65w or 35w even (2120T). Any advice on a new chip to match the 6670 ?
say 1600x900 on nfs-therun, bf3

You could just turn HT and a core off on the 2600k.

HT off, 2 Cores - 205w 4.2 load. HDD failure again after that. This brick won't cough up any extra. Multimeter 11.88v. I'd like to stick with the current power and cooling. Reducing cores does not sit well. I suppose like running a ferrari on 2 cylinders. HT off too? Considering these limits on the CPU, why keep it in ? You know what we are like.
It's a 5.2GHz chip, although I'm (with some effort) looking at the poitives of 4.2 and 8 threads. With all respect, what would you do Bob ?

I should add that this is HTPC is connected to a 1600x900 3D DLP projector and is used for encoding vobs, burning (20%), gaming (10%) and viewing (70%).

A 2600k OC'd to 4ghz with 3 cores and no HT will stomp most any of the locked multi SB CPUs.
Then again given your uses a SB dual ought to be just fine too, though encoding will take longer.

A 2600k OC'd to 4ghz with 3 cores and no HT will stomp most any of the locked multi SB CPUs.

Click to expand...

Agreed. And it's no use going backwards. It stays. Thanks