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In Reply to: RE: Current measurements on powersupply P4 pin posted by Ryelands on April 06, 2009 at 12:25:52
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cics wrote:
What VID are you using to get Vcore of 0.75V (and host @140)? Noticed that with EIST off, VID can go lower!
Now that you pin me down, I have to say that I'm not sure what VID is in this context and my note may have been muddled as a result.
Whatever, in the BIOS's MIT menu, there is a setting for CPU Voltage Control . This is set to 0.75000. (Just below that is a note that the "normal" CPU Vcore is 1.15 v.)
With this setting (I've just checked), CPU-Z reports that Vcore is 0.704 but I have also noticed that the BIOS menu "PC Health Status" says that it is 0.724.
I know what VID is in general terms but as to exactly what these figures mean and which Vcore reading is right, I've no idea.
I have run the board with CPU Voltage Control set as low as 0.65 but, especially when cold, it tended to restore defaults on powering up so I settled on 0.75 and left it at that. (Some report SQ differences after making minute changes to CPU Voltage Control but I can't hear any.)
I have a hunch you're right about things being more stable with EIST off but I've not tested it systematically.
Dave
VID is an 8 bit code set from BIOS to CPU. Each VID reference relates to Vcc specifications as per Intel. You have VID of 0.75000 set - I'm currently testing 0.73750 (lower values are unstable). The "normal voltage" BIOS message is a CPU setting (each is set by Intel). I have one E7200 at 1.15 and another at 1.21 (which does 0.83750).
Can you measure overall power consumption using your fluke on main 12V supply to P24 & P4 (i.e. use one PSU).
cics wrote:
Can you measure overall power consumption using your fluke on main 12V supply to P24 & P4 (i.e. use one PSU).
Just to be absolutely clear, the figure below refers to the Gigabyte G21 MoBo.
When playing flac-format music data without upsampling with the CPU clock at 140MHz, VID at 0.75000, PSU at precisely 12v, EIST off, 512 MB Kingston "ValueRAM" and a "Full Monty" cMP2 setup, the motherboard and CPU typically draw about 1630 ma.
Allowing for dissipation in the "pico-PSU", call it 1600 ma or about 19 watts. Last time I measured this, it came out slightly higher (see cics's earlier request for this measurement). I don't think I've tweaked anything significant in the meantime but, as the first measurement was taken with a different meter on its 10 amp scale, I'd tend to put more faith in this one.
BTW, after a tedious to-and-fro session, it's clear that my setup at least sounds better with EIST OFF . Who'd have believed it mattered?
That'll do me for current measurement for a while - it seems oddly emotive for such a humdrum topic.
Best
Dave
Thanks.
Got SQ improvement with VID 0.73750 (Vc as per CPU-Z shows 0.704V). As expected, CPU temperature dropped nicely by 4-6°C. Now testing VID 0.73125 (Vc is 0.688V) which is the lowest stable VID in my case.
Setting Host Freq to 150 and upsampling to 192k @145db SNR should yield overall power consumption below 20W (with 256MB RAM)!
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