DDR Boostage Voltage Fluctuation

cinders · 12-08-2004, 10:33 AM

Should this happen?...

I've been measuring my VDimm voltage from the mosfet leg and my voltage varies constantly up and down between 3.32v and 3.37v - surely this isn't correct?...

bacon · 12-08-2004, 10:35 AM

Quote:

Originally Posted by cinders

Should this happen?...

I've been measuring my VDimm voltage from the mosfet leg and my voltage varies constantly up and down between 3.32v and 3.37v - surely this isn't correct?...

what does the booster read?

cinders · 12-08-2004, 10:37 AM

The booster reads 3.4 sometimes 3.3... I wonder if it's broken. I should take it out really, then measure the mosfet again to see if it still fluctuates slightly.

bachus_anonym · 12-08-2004, 10:55 AM

OMG, people.... this is not a huge fluctuation... ~0.05v, give a break

OCZ DDR Booster, as you know displays only x.x not x.xx. so if your vdimm fluctuates 0.05v and you had it set to, say, 3.58v it will switch between 3.5 - 3.6 .....

cinders · 12-08-2004, 11:03 AM

OK here's some more information....

If I boot windows to the logon screen and set the voltage to 3.300 using my voltmeter it's rock solid - it sits there and doesn't move - spot on!

I then reboot and watch the voltage fluctuate slowly as it boots up then it hits the windows logon screen and it's back to 3.309 so there's 0.009v different - nothing to worry about...

I then reboot with the memtest cd and take readings as it begins - at this point the voltage fluctuate's up and down between 3.186v and 3.236v.
This is what I don't think is correct - is my booster faulty or maybe it's not getting enough juice to keep a steady vDimm whilst the memory's under heavy use.

Reboot back to windows and take reading - back to 3.311v - rock solid again.

Whats happening?..

Cinders.

bachus_anonym · 12-08-2004, 11:10 AM

ok, on this board when system is IDLE vcore is lower than when it's under LOAD. there's totally opposite situation with vdimm - under LOAD mem voltage dips down.
it's normal as i've never seen a board NOT FLUCTUATE at all underl LOAD, never....

cinders · 12-08-2004, 11:15 AM

Quote:

Originally Posted by bachus_anonym

ok, on this board when system is IDLE vcore is lower than when it's under LOAD. there's totally opposite situation with vdimm - under LOAD mem voltage dips down.
it's normal as i've never seen a board NOT FLUCTUATE at all underl LOAD, never....

OK makes sense, I was just a little worried seeing the voltage fluctuate around like that, thought it would be solid.

So say I want to burn my VDimm in at 3.30v - What do you suggest?..

Do I set it to 3.30v in Windows because if I do that it'll only be running at around 3.186-3.236v in memtest under load...

or do I set it to around 3.30v in memtest under load and forget about windows voltage readings until I've done burning this stuff in?...

your help is appreciated - i just wanna get on with burning this memory in!

Cinders.

.

cinders · 12-09-2004, 12:55 PM

OK - Can someone help me out here??.. The voltage in my bios is set to 2.6v.

This morning I set the Booster at 3.3v whilst at the bios screen. I left mem test running all day. When I checked the Booster was saying 3.5v - I then rebooted and went in to the bios screen and it was still reading 3.5v

Each time I set the voltage on my booster it seems to go out of sync. Is the booster faulty?...

Dani · 12-09-2004, 01:19 PM

DFI LP 250GB:

4.1V in Booster
3.93V from mosfet
3.87V in SmartQuardian

cinders · 12-09-2004, 01:23 PM

Quote:

Originally Posted by Dani

DFI LP 250GB:

4.1V in Booster
3.93V from mosfet
3.87V in SmartQuardian

I'm just talking about readings from the booster here, they're going up and down by a few 10ths of a volt all the time. I might set it at 3.3v and see 3.1 or even 3.5 on the booster.

I suspect the Pot is at fault - I'm going to replace it with a higher quality one this weekend and move it to the other end away from any heat.

Formann · 12-10-2004, 04:47 AM

My DDR Booster in an Aopen i855 Dothan mobo.

Set to 3.0v while in BIOS.

In windows it reads 3.1 .. with load it drops to 2.9v

Now thats fluctuation.

PSU was FSP 300w but the 5v rail was at 5.21 ROCKstable.

On my K8NS Ultra939 it drops 0.1v when im running high vdimm. From 3.8 to 3.7

HavenÂ´t tested it on MSI K8N yet. Maybe ill do it this weekend

cinders · 12-10-2004, 04:55 AM

If I touch the pot with my finger the reading jumps all over the place. I definately think the pot is fault, I'm replacing it tonight.

mikead_99 · 12-10-2004, 07:30 AM

Quote:

Originally Posted by cinders

If I touch the pot with my finger the reading jumps all over the place. I definately think the pot is fault, I'm replacing it tonight.

I replaced the pot on mine as well, mostly because I don't like the sensitivity of the stock version. Too touchy being a single-turn. Anyway, there was a thread when the Booster first got on the streets where someone posted the same complaint. Not so much about what the LED reads, who cares what it says? But about the droop of this thing under load. Even with the new pot I get about .2V droop at lower voltages (3.1V - 3.3V) as seen on a dmm. It does seem to do that less as I increase the volts, but basically if I want say 3.2V to the dimms, I need to overshoot to 3.4V on the Booster. If it droops below what my mem wants, errors of course, but idling above what they want doesn't really seem to hurt. Apparently some level of drooping is "intended" for this product as an OCZ rep explained in that previous thread.

cinders · 12-10-2004, 08:02 AM

What type of pot did you go for?... I'm not quite sure what to replace it with!...

If you remove the booster and run the memory at normal voltage (through the bios) then put the memory under load, does the voltage drop in the same manner as it does with the booster?...

I've looked for the threads on the booster but can't find the one you mention.

Cinders.

OPPAINTER · 12-10-2004, 08:51 AM

I believe the booster runs off of the PSU 12V line.
If your PSU 12V line has a lot of fluctuation then the mem voltage will fluctuate.

I think this is how it works

OPP

mikead_99 · 12-10-2004, 08:58 AM

Quote:

Originally Posted by cinders

What type of pot did you go for?... I'm not quite sure what to replace it with!...

If you remove the booster and run the memory at normal voltage (through the bios) then put the memory under load, does the voltage drop in the same manner as it does with the booster?...

I've looked for the threads on the booster but can't find the one you mention.

Cinders.

I replaced it with one of those little square 10k cermets. No mounting tabs like the stock pot so I had to RTV the pot to the pcb.

And no, no VDimm droop without the booster, or with a regular V-mod. I've used it now on a few boards and seen the same thing. My first go with it was on a P4C800 that I had V-mod'ed but couldn't run higher then 3.65V due to psu limitations. Mod was rock solid, Booster wasn't. Same on this MSI K8N Neo2. It's just the way this thing behaves. And yes, plenty of cooling on the Booster.

@ Opp: I did initially have an Antec psu with too weak of a +12V line to handle everything I threw at it. I have replaced it with the OCZ 520, and have monitored all rails, no sagging/fluctuation there.

SnipingWaste · 12-10-2004, 09:27 AM

Memtest #5 will make the memory pull heavy amps and voltage will drop some. The better the voltage regulator the lower the voltage drop. The voltage regulator on my mobo will drop .4 volts on test #5 so now im feeding my dimms direct from the PSU3.3v rail and now only drops .02V. The voltage drops you are seing is normal and shows a very good voltage regulator. Don't worry about it till you see .08V to .1V drops.

STEvil · 12-10-2004, 04:09 PM

You guys need to make sure the PSU is delivering stable amperage as well as voltage.

If either drops due to system load then the booster may fluctuate.

TCCD pulls big amps, more than BH/CH chips.. so be carefull

Pimp! · 12-13-2004, 11:30 AM

man im having major problems with mine, if i set it to 2.8 it jumps to 3.1 within 3 minutes...

no matter what voltage i set it always goes up from what i set it to...

ryanpgroovy · 12-13-2004, 11:34 AM

during the boot the voltage may go down, then when you boot windows / memtest the voltage will go up to the normal voltage

Also under extreme load you may see a voltage drop. Dependant on your psu

Also variances in hundreths of volts during steady load , are normal.

Pimp! · 12-13-2004, 11:36 AM

if its turned all the way down, it steady as can be, fluctuates max of 0.005

but once i hit it up to 2.8, and not turn it any more, i put the mutimeter on the board and it just goes up from there, reaching 3.2 after a few minutes

Pimp! · 12-13-2004, 11:36 AM

Quote:

Originally Posted by ryanpgroovy

during the boot the voltage may go down, then when you boot windows / memtest the voltage will go up to the normal voltage

Also under extreme load you may see a voltage drop. Dependant on your psu

Also variances in hundreths of volts during steady load , are normal.

but this is just sitting at idle...

ryanpgroovy · 12-13-2004, 11:36 AM

Pimp ,

What PSU are you using.

Pimp! · 12-13-2004, 11:40 AM

TTGI super flower 550TS. will try my 400w antec soon probably

Holst · 12-13-2004, 11:41 AM

Quote:

Originally Posted by OPPAINTER

I believe the booster runs off of the PSU 12V line.
If your PSU 12V line has a lot of fluctuation then the mem voltage will fluctuate.

I think this is how it works

OPP

I took mine appart and it works from the 5v line mate

BUT part of the circuit that sets the voltage runs from the 12v line (follow the traces on the board) so I think that fluctuation in the 12v line may explain this variation..