DFI using 5v rail for ram not 24/7 stable?

[mdzcpa]

I've been running one of my DFI NF4 mobos at 3.4v since day one almost 4 weeks ago. No issues. Runs 24/7. Just a small fan on the corner is fine.

[krille]

Excellent! (However shortening the mobos life and stressing it to max won't really show up in a few weeks, but hopefully it'll work out just fine.)

Hopefully the new Bullhead will have an active mosfet cooling solution stock.

[DarkManX_BG]

Running off the 5V for 2 weeks so far (switched that jumper 20 minutes after getting the mobo ), no stability problems whatsoever...

I have NO extra cooling for the mosfets, only thing that cools the RAM is the fan on the XP-90...

[cantankerous]

dang man. Have you ever felt that heatsink in the corner with no fan on it? It's dangerously hot.

[bobmanfoo]

dang man. Have you ever felt that heatsink in the corner with no fan on it? It's dangerously hot.

is it hot all the time or just under load? anyway, i wonder why they opted to put a smaller heatsink there compared to the others

[HKPolice]

What about the 3.3v rail = vdimm mod? Can it be safely done when set to use 3.3vrail for vdimm instead of 5v rail?

This is the most stable way of getting voltage to the dimms IMO.

[Grayskull]

The "new" Bullhead as you call it, doesn't require any cooling. It uses a different architecture and runs cool. Even the very first bullheads were off the 5V rail without thermal issues.

Excellent! (However shortening the mobos life and stressing it to max won't really show up in a few weeks, but hopefully it'll work out just fine.)

Hopefully the new Bullhead will have an active mosfet cooling solution stock.

[S0nic]

I still didn't receive my PC4000 VX to test how hot the mosfets will get, but I have an 80mm case fan at the top of the case (directly above the mosfets) which I hope will be enough cooling..

btw what's bullhead?

[phobos]

I still didn't receive my PC4000 VX to test how hot the mosfets will get, but I have an 80mm case fan at the top of the case (directly above the mosfets) which I hope will be enough cooling..

btw what's bullhead?

Bullhead is the code name of the new ATI motherboard.

[DarkManX_BG]

dang man. Have you ever felt that heatsink in the corner with no fan on it? It's dangerously hot.

Just checked it... trying to dig up an old 80mm fan right now. It's really VERY hot, thanks a lot for the hint!

[Eversor]

I won't use the 5v rail other than for testing, even did a vdimm = vio.
When using from the 5v, even at 3.5v, when memtesting, the pcboard around the dimm mosfets on the top is REALLY HOT, even with a fan. It seems too much current there and the pcboard heats up alot. I personally will use vdimm = 3.3v.
For more consider a ocz booster, at least your board is safe.

It was enough for me when my nf2 lp B blown up 2 times the same pcboard trace probably due to high vcore.
And if Oscar says u cant use 5v for everyday, you can't! Even more for 24/7 load use.

If u have doubts just memtest #5 with a finger next to the mosfets and feeding from 5v, and you'll know what i mean.

[mesyn191]

All you need is to have a fan pointed at it and it doesn't get very hot man, just my finger on mine and its only a little warm under P95 and I've got my 5v line overvolted a little too.

[mdzcpa]

All you need is to have a fan pointed at it and it doesn't get very hot man

Yep, I have a small fan there and even under load the heatsink is a cool as a cucumber Now, without any fan, the heatsink gets damn hot!

Another point, the area heats up only under load. Email, web, and many other less intensive tasks don't heat up at all even without a fan.

Last, does someone have link where Oscar said that you cannot run the jumper in 5v everyday? I'd like to see that. Because if you email DFI tech, they will tell you that you can use the jumper as an everyday setting. They will only caution you that cooling the area should be considered.

[boostdfd3s]

well, all i know is they better accept RMA's if the boards start to fail from everyday 5v use

[c42]

I hope it doesn't turn into a problem. Mine is in route and should be here thursday. My vid card should ship out tomorrow, so hopefully by friday I can test it before I go out of town! I'm building this comp for everyday use, and got this board and the ocz vx thinking that I should be able to run 24/7 stable with correct settings. If I can't run the 5v rail for the vdimm 24/7 stable I'll be switching to tccd and perhaps a different board =\.

[boostdfd3s]

Well if problems develop from 24/7 use, hopefully they will arise shortly after the ATi board reaches market, which the reps say the 5v mosfet doesnt even get hot from normal use

[Eversor]

I won't use that for 24/7 operation. Maybe is just memtest #5 that really stresses the mosfets.

And what i said it's hot is not the mosfet sink, but the pcboard itself, on top, next to the mosfets. I garantee u running memtest with 5v you can't keep ur finger in that pcboard area. The boards traces get really hot, wich, i think, is nothing good.

EDIT:

I can't find the post, but it was one from OPB saying he was talking to oskar wu, and he told them the 5v rail should only be used for testing purposes.

[mdzcpa]

I can't find the post, but it was one from OPB saying he was talking to oskar wu, and he told them the 5v rail should only be used for testing purposes.

Well that's 100% contrary to what DFI reps are telling everyone. And at least inconsistent to what the manual says.

BTW, my PCB does NOT get that hot. A small 40mm 2000 rpm fan is enough for me to keep my finger firmly planted on the PCB while running memtest #5. I just tested it now.

Common sense dictates that if it was a real problem to have the 5v jumper they just would not have included the feature there to use in the first place.

Everyone is being far too concerned about this.

[bachus_anonym]

that's the post - http://www.xtremesystems.org/forums/...64&postcount=1

Yeah, you guys are just too concerned about that... I don't think that they would give end-user an option like that if there was a significant danger of killing the board...

[Eversor]

Strange, mine get's frekin hot. That's why i'm not using the 5v right now...

[cantankerous]

stress or not its very hot for me. I dont use it. I wish there was a way to get it working from the 3.3v rail of the psu.

[S0nic]

stress or not its very hot for me. I dont use it. I wish there was a way to get it working from the 3.3v rail of the psu.

there isn't?? can't we get 3.3V or 3.4V from the 3.3v rail if we adjust the rails?

[c42]

Also the main thing he stated was that it would get extremely hot IF YOU USE 3.3 or LESS with the 5v setting! So there should be no need for this in the first place. They also stated that, yes, it does get hot with more than 3.3v on vdimm with the 5v option enabled, so to actively cool that area.

[mdzcpa]

Strange, mine get's frekin hot. That's why i'm not using the 5v right now...

Dont get me wrong, mine gets hot too with no fan. Hot enough to burn I think. But a small fan seems to be very effective at dissipating the heat.

I'd never consider using the jumper without localized active cooling.

[mdzcpa]

that's the post - http://www.xtremesystems.org/forums/...64&postcount=1

Thanks for the link!

It seems Oskar never said anything about not using the 5v jumper for 24/7. Here's what was said:

oskar: However, even though user switch 5v rail source to do vdimm above 3.3v, the heat is still unbelivable hot there. therefore, that's why we use the 4000~10000 hours 105c very good caps on that area. I would definitely suggest users can give that area some air flow to reduce some heat from there.

So it looks like DFI has planned for heat and engineered it accordingly with better caps.

Well....I feel even better about running 24/7 now
Of course a fan on the corner is a must!