Gigabyte GA-MA74GM-S2: AMD 690G, Take 2

alexx · **Posted:** Mon Mar 23, 2009 7:27 am

btw, it still does not explain why with the same power meter I do not achieve the same (bogus) readings when manually undeclocking/undervolving the system. C&Q does more I guess, than just lowering the Vcore...

nutball · **Posted:** Mon Mar 23, 2009 8:05 am

alexx wrote:

btw, it still does not explain why with the same power meter I do not achieve the same (bogus) readings when manually undeclocking/undervolving the system.

No, indeed not, but then in the absence of an explanation why it's acting up in the first place it's hard to tell what's going on.

I'm wondering whether it's got something to do with the power factor correction. The meter I have (a Brennenstuhl) shows fairly constant current but cos(phi) starts wandering all over the place when I start seeing these funny readings.

alexx · **Posted:** Mon Mar 23, 2009 8:31 am

so am I

http://www.brennenstuhl.de/content.php? ... etails=809

it's Digital Weekly Timer HBT 100

you have the same?

I was also thinking if this is not someting PFC related, but how to check?
Actually, I am not sure anymore that what I see on this things is actually a reality :-)

alexx · **Posted:** Mon Mar 23, 2009 8:34 am

no, actually I have "the Wattage and current meter PM 230"
looks kind of the same:
http://www.brennenstuhl.de/content.php? ... etails=807

nutball · **Posted:** Mon Mar 23, 2009 9:24 am

Yes the PM230 is the meter I have.

During the times the power reading is fluctuating back-and-forth from ~58W to 18W, if I put it in the mode which shows current rather than watts the current is steady at about 0.28A, whereas the cos(phi) is alternating between ~0.21 and ~0.85.

alexx · **Posted:** Mon Mar 23, 2009 12:34 pm

good idea. So I've redone all the tests and these are the results:

Code:

Cool & Quiet

Freq       Current, A       (load)          Power, W       (load)
2700       0.27              0.34           60.6            76.33
2600       0.26              0.33           58.4            74
2400       0.25              0.31           56.1            69.6
2200       0.24              0.28           54              62.9
2000       0.24              0.28           54              62.9
1800       0.24              0.27           54              60.6
1000       0.22              0.24           49.39           53.88

Manual underclocking/volting: multiplier: x5, Vcore: 0.8v
           0.20              0.21           44.9            47.2

this is as low as I could get with this setup; not impressive, but I can live with it.

Gigabyte GA-MA74GM-S2: AMD 690G, Take 2

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