Is there any way to measure PCI Power Usage?

minifridge1138

macrumors 65816
Original poster
Jun 26, 2010
1,039
64
Hello Everyone,

I'm wondering if there is any way to measure the amount of power being used by the PCI rows on the LB.

I' thinking of adding a GT 640 for an additional 65W. I know it isn't a powerful card, but it's a cheap way to get 10X the number of cuda cores I have now (GT 120 has 32 cuda cores). I don't need to power a display with it.

I already have:
Apple 5870 = 75W (6 pin) + 75W (6pin) + 38W (PCI) = 188W (AMD Spec)
Apple GT 120 = 50W (PCI) = NVidia Spec

The GT 640 would only use 65W from the PCI lane, so i'm good on paper. I'd just like to see what I'm actually using.

thanks!!!
 

Thessman

macrumors regular
Dec 8, 2005
147
29
GR
Hello Everyone,

I'm wondering if there is any way to measure the amount of power being used by the PCI rows on the LB.

I' thinking of adding a GT 640 for an additional 65W. I know it isn't a powerful card, but it's a cheap way to get 10X the number of cuda cores I have now (GT 120 has 32 cuda cores). I don't need to power a display with it.

I already have:
Apple 5870 = 75W (6 pin) + 75W (6pin) + 38W (PCI) = 188W (AMD Spec)
Apple GT 120 = 50W (PCI) = NVidia Spec

The GT 640 would only use 65W from the PCI lane, so i'm good on paper. I'd just like to see what I'm actually using.

thanks!!!
1 istat
2 Hardware Monitor
 

Inconsequential

macrumors 68000
Sep 12, 2007
1,977
1
Hello Everyone,

I'm wondering if there is any way to measure the amount of power being used by the PCI rows on the LB.

I' thinking of adding a GT 640 for an additional 65W. I know it isn't a powerful card, but it's a cheap way to get 10X the number of cuda cores I have now (GT 120 has 32 cuda cores). I don't need to power a display with it.

I already have:
Apple 5870 = 75W (6 pin) + 75W (6pin) + 38W (PCI) = 188W (AMD Spec)
Apple GT 120 = 50W (PCI) = NVidia Spec

The GT 640 would only use 65W from the PCI lane, so i'm good on paper. I'd just like to see what I'm actually using.

thanks!!!
What are you worried about?

You've got 75W from the slot irrespective of what else is plugged in to other slots.

istat menus shows power draw (version 3 NOT 4). Only accurate to +/- 10% I'd imagine.
 

Inconsequential

macrumors 68000
Sep 12, 2007
1,977
1

666sheep

macrumors 68040
Dec 7, 2009
3,623
211
Poland
Yes, power draw reading works in 4.05 I have.

I understand that iStat reads values from hardware sensors, correct? If so, it should be as accurate as sensors are.
 

Inconsequential

macrumors 68000
Sep 12, 2007
1,977
1
Yes, power draw reading works in 4.05 I have.

I understand that iStat reads values from hardware sensors, correct? If so, it should be as accurate as sensors are.
The sensors arnt going to be accurate to much more than 5%, or even if we are lucky 1%.