Originally posted by: cpmee
Originally posted by: jimmor
Originally posted by: cpmee
Originally posted by: jimmor
Originally posted by: Microsystem
.......I measure VAGP with a digital multi meter
Default: Normal 1.61V and High:1.62V (this wonder me too)
Your bios default "Normal/High" measured values for Vagp seem a bit odd to me ---> hardly worth having two different bios settings ?
My experience of measuring Vagp on 4coredual-vsta and 4coredual-sata mobos is that it was 1.59 and 1.64 volts for same bios settings.
OK, I got around to measuring my vagp, per the vr-forums diagram.
I got Normal = 1.597 volts
Auto = 1.605 volts
High = 1.605 volts
Since my meter also has a temperature probe, I measured temps along with the voltages.
With an old pci card in, the agp mosfet has a temp of 55C at all voltages. Interestingly, without any video card in, the temp is 34C. Ambient was 22C in all cases.
55C before the vagp mod is pretty high, and given the tiny space available for a sink, I dont think a sink does much jimmor. I think some sort of an air hose blowing on the mosfet is what is needed.
So also pointless having more that one Vagp setting with your particular mobo ---> what have asrock been doing to some of their 4coredual-sata2 mobos ---> weird "new" not so good bios cpu overclocking settings, and now weird bios Vagp settings ?
However, it probably now makes a bit more sense as to why lots of 4coredual users appeared to have weird issues trying to achieve high overclocks ---> a problem which my "version" of 4coredual has never suffered from ?
Yes, the Vagp MOSFET can run into mid 50's (and not much higher, even with 2v vagp ---> it runs from 3.3v supply, and higher Vagp means less volts accross Mosfet) ---> And yes, I have fitted a small "tall" heatsink onto it, and it does help ---> mind you it probably also benefits from the fact that I have a fan fitted inside my case whose job is simply to circulate cool air around ?
The Northbridge heatsink also gets hotter, which is why I fitted a 40x40mm fan.
And just for interest, a main reason that Asrock removed the "EIST/Speedstep" options from the bios was because asrock tech determined that some early Northbridges had overheated and failed because of being deprived of cpu heatsink cooling air when EIST/Speedstep had stepped the fan down to low speeds ? Obviously decided disabling the speedstep functions was easier and much cheaper than fitting a fan onto the northbridge heatsink ?
OK, I did the vagp mod. I penciled the R2471 resistor from a value of 1.889Kohms to a
value of 1.779Kohms. My vagp then went to 1.705 volts from a value of 1.605 volts.
That mosfet also increased in temp from 55C to 59C. The northbridge heatsink may have
increased in temp, but only slightly. After the mod, the temp was only 32C, measured
at the center of the northbridge sink, 22C ambient. I didnt measure it before the mod, but it was fairly cold. Also when I first got the board, one of the first things I did was to remove the northbridge sink and wipe off the Asrock thermal paste to write down the numbers on the chip. I then reapplied AS Ceramique on the chip, so that helps with my nb cooling.
I got 285fsb, OCCT stable, up from 280fsb OCCT stable.
In my case, I cant put in a tall mosfet heatsink. Because of the heatsink on my vga
card, my total area I have to work with is about 1cm long X 1cm wide x 1.5cm high.
Besides my air hose idea, the other idea I have is to get a piece of copper sheet,cut
it to the proper size, fold it up like an accordian, and attach it to vga heatsink.
The spring action would then keep it against the mosfet, and it would benefit from the huge area of the vga heatsink.
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