Epox 9NDA3+ and undervolting

[Per Hansson]

Hi, I've got a Epox 9NDA3+ nForce3 Ultra experiencing some seriously exsessive coil noise from the middle coil in the VRM section, hot gluting the coil does not help

I know, from info from the seller, that the board did not have this issue when it was run at a lower voltage with a Winchester CPU, mine is a ClawHammer, defaulting to 1.50v but the BIOS lowest setting is +0.05v (WTF!)

I am running BIOS v09/15/2005 which is the latest, the changelog from this BIOS release:

Code: Select all

Added: Support F75121 and Atxp9 negative Vcore voltage adjust

http://www.epox.nl/downloads/bios/?obj_product_id=274

I have a pretty lengthy thread about this on badcaps also link but what I was curious about now was the ability to undervolt with the mobo... And I guess you guys here should know best...?

[Le_Gritche]

I am running BIOS v09/15/2005 which is the latest, the changelog from this BIOS release:

Code: Select all

Added: Support F75121 and Atxp9 negative Vcore voltage adjust

[...]
I was curious about now was the ability to undervolt with the mobo... And I guess you guys here should know best...?

That motherboard is not in SPCR's list of undervoltable motherboards. It means that either you can't set at least -0.2v for the Vcore OR that it undervolts but nobody reported it in the dedicated thread.

Search with google you will find a couple of reviews. That one from AnandTech shows only over-volting capacity.

You wrote that the latest BIOS adds "F75121 and Atxp9 negative Vcore voltage adjust". Look in your BIOS to see if that changed the CPU voltages you can choose from. Otherwise it's probably that Atxp9 is somehow related to 'sleep mode' or 'suspend to RAM'.

Go in OCWorkBench's Epox section, they have a dedicated thread for your motherboard. Topic: Epox 9NDA3+ Socket 939 NF3 Ultra board. There are probably more overclockers than undervolters there, but they are very helpful and I'm sure they know each feature of the board and BIOS.

[Per Hansson]

As I said with the latest BIOS in which changelog it is stated there is undervoltage capability the only settings for vcore are the ones you see in the Anandtech review you linked, i.e. +0.05, +0.1, +0.15, +0.20

Atxp9 controls the CPU multipler via VID pins, i.e. it is a chip used so you get software control, instead of the old way with dipswitches...

F75121 is a voltage controller chip, but my board seems to use a ISL6559CB voltage controller, so maybe this undervoltage capability only relates to a specific revision of the 9NDA3+

To clarify: On my rev 1.0 9NDA3+ there is a Atxp9 controller chip along with a ISL6559CB voltage controller chip...

[Per Hansson]

Just found out from a guy at badcaps who asked Epox about the differences between the two different revisions of the 9NDA3+

the only difference between Rev1 and 2 was a different CPU Voltage regulator chip

So case closed