Maximus Formula dead, important info inside

[Tony]

Guys

If you have the Max formula before you push this board hard make sure you reseat/make sure the heatsinks covering the mosfets are sitting correctly and doing their job. i just started testing Q6850 at 4GHZ 1.5V with 8GB ram 1000MHZ 1.8V and within 5 mins 1 phase has blown off the board thru poor cooling to the fets.

See pics below:

4 fets blown...awesome board while it lasted:


Here you can see the poor contact from the heatsink...4GHZ load was just to much





Be clever and make sure the heatsinks are seated right...mine were not it seems

Side note, CPU was watercooled and had a bloted thru backplate, in no way was this board bowing thru to much pressure on the CPU mounting. Applied force to CPU was 55LBS which is well within Intels specs, Ambient room temp in the workshop is 12C also and i had fans blowing over the board.

[Cronos]

It is better to remove those heatsinks altogether.

Also, notice that installation of CPU heatsink or waterblock without backplate will lead to MB warping and some FETs in the centre may loose contact with heatsink.

[Tony]

had the backplate man...its how I helped design OCZ's new block

This is just poor QC on the board....the guys here push boards hard and this should not happen

[SoulsCollective]

Damn, that's really quite dodgy. Still, could be just the one bad apple.

[newls1]

Damn, that's really quite dodgy. Still, could be just the one bad apple.

Nope, TONY is 100% correct. My Max Formula had the worst contact on the FET's.

[Kunaak]

its not a Maximus Issue.

its a total Asus Heatsink Issue.
I've had many many 775 boards in the last year or two with these mosfet heatsinks on them.
they never make good contact with all mosfets, especially in actual use of the board, when they start to warp alittle from just about anything. crooked case, torqing the board. heavy watercooling pulling the board. heavy heatsinks warping the board over time.
waterblocks with no backplate, or cheap backplates.
every single time I took my heatpipe/heatsinks off the board, the contact in the thermal pad was near non existant in the middle. or very inconsistent.

what I resorted to, was nuts and bots, and my own back plates I made from strips of metal and a drill.
now, I dont have to worry about bowing making the mosfets lose contact.

in my opinion, these heatsinks should come with back plates by default.

[BenchZowner]

Kunaak is correct.
That happens even with the Intel Box Cooler.
Poorly performing heatsinks & heat-pipes, poor contact, poor mounting "system".
The only thing that's not poor is the price...

[iadstudio]

is there any way to tell without completely removing the heatpipe assembly?

[Leeghoofd]

Soz for ya loss Tony... but you will get over it

Off Topic : Tony any news on the OCZ Phase cooler ? Will it be produced in big masses and also for Europe ? That would be cool

[situman]

Wasn't the so called 8 phase power whatever suppose to keep things cooler? I guess not

[BenchZowner]

I couldn't take a better shot because of the lighting conditions of the room, but

[Leeghoofd]

I think like Kunaak suggested only backplates on all the heatsinks with screws will make the board more rigid against flexing... gonna take a piccie of mine with the QX cooler on it... Seems pretty straight here when you quickly look at it, but there's a clear bow... but I've seen even worse with some P35DS4 mobo's I put together...



Which baord is that Bill, P5E3 ?

[rioja]

yea, bad contact on mosfets is style of asus
my p5k3 dlx has same issue, backplate wont help here

[BenchZowner]

One more thing... I don't know why, and if it's only a feeling of mine, but I feel/remember that the old hotties ( the DFI LanParty nF4 SLI-DR back in the... AMD powah days for example ) needed an enormous amount of pressure ( de-centralized pressure actually ) to bend...hardly.
New boards ( I feel, I repeat ) seem to bend easier [ I'm not sure, could be wrong of course ]

Edit: Mobo in pic is my beloved Asus P5K3 Deluxe

[.OCX]

That sucks Tony, but at least the informations out. I'm gonna give my board a hard look over this weekend and see what the contacts are like, make sure nothing has burst.

[Tony]

I received the board from Asus so its not my money but I do feel this is a serious issue hence I posted.

I have NEVER blown a board up like this before, the PCB looked as flat as it was unloaded with the block etc but obviously it was not.

5 mins in memtest testing 8GB of ram at 1000...boom board gone...in went Striker II ;-)

[mrcape]

Yup those asus sinks/tape have notoriously bad contact.

It sucks but I have to say that's a pretty cool pic of the blown mosfets. I like the microcool mosfet sinks because they are tiny, so you can be sure you cover all the surfaces with no gaps.. I used those on a P5K dlx and it worked great with some airflow.

[Z3R0-CooL]

i use backplates and water blocks on mosfets... typically the board bends when u install heavy heatsinks therefore the mosfet heatsink loses contact with the mosfets.

[teko]

Just got the board today (awsome price, 100USD for a brand new one, stupid shop :p ) and after pooling all the cooling of to install thermalright instead, I noticed that the stock cooling had perfect contact with the mosfets. It might have been a problem with a batch of them? I got black thermal pads on mine.

[rioja]

sure new board has good contact, but it will bind easily once you install heatsink. and loose contact.

[BenchZowner]

Initially they seem to make good contact.
After you install a cooler ( even Intel's Box cooler ) they don't make good contact in the middle because they board bends ( not like Beckham )

Edit: heh rioja, perfect timing man

[Kunaak]

these need backplates bad.

examine tonys own photo and you can clearly see the pressure is greater at the edges, meaning there was little contact in the center.
plus, the contact is best along the outter edge of the heatpipe side of the heatsink, so mosfets on the other side of the heatsink are more likely to blow out.

which is exactly where tonys burn marks are.

[kup]

What screw size would I need to reattach them all better?

[Durkadurka]

I ordered some rugged Mosfet-backplates from Chilled PC Uk.
Works just fine!

[Cronos]

5 mins in memtest testing 8GB of ram at 1000...boom board gone...in went Striker II ;-)

Memtest is single -threaded and creates very very small load on CPU. This is highly unlikely the reason was solely MOSFET overheating.
Under this low load, taking into account highly efficient power design on this board, those FETs power dissipation was not nearly enough to make the blow. They don't even need to make any contact with heatsink - heat can easily travel through PCB.

I think the FETs were somehow defective in the first place or maybe something gets here and shorted them.

On my P5K-Pro (which has similar efficient 8-phase power design) i removed all sinks from mosfets, and with minimum air flow around, those FETs stay cool even under Linpack64!