I see that you use a watt meter to measure watts from the wall plug to the system power supply and it seems that you indicate this is what the system is drawing from it's power supply, but powers supplies are never 100% efficent (50 to 85% depending on current draw and design, maybe!) although it's good to know what the power supply draws from the wall and my pocket. For example my 480 watt ps can draw 9 amps max times 120 volts for a total of 1080 watts from the wall. Is there any way you can show us real watt draw form the PS output or maybe just the 12vdc, 3.3vdc and 5vdc. I think? this would be of help to members when buying a PS because the PS output ratings for say a 400 watt PS can vary trememdously at 3.3 ,5 and 12vdc. Thanks and keep up the good work............BigPipe
You are correct about that. The best thing is to measure between the PSU and product instead of measuring outside the PC -> measuring the PSU's actual draw in 110V/230v from the buildings power circuit and thus not how many watts of 12V+3.3V+5V being pulled by the computer from the PSU. Fact is that we are limited in measuring power consumption for the graphics card, specifically the 12 volts rail is very important in terms of amps. Unfortunately a graphics card draws juice from both the mainboard's PCI Express bus and the additional power connector that feeds straight from the PSU. It's extremely difficult to measure the 12 volts rail for them both unless you pull some seriously tricky stuff and even then I'm not sure the results would even be reliable. The total power Wattage we measure is indicative and the dilemma you present I have been thinking about quite often to see if we could improve the measurement. Basically I end up with the option not presenting the wattage at all or doing it this somewhat simplistic yet informative way. I personally do believe that presenting the data as we do gives a very good overall indication as the actual power draw from the power circuit is pulled directly from the PC that is measured.
how to measure current draw Hey i see the delimma you face in measuring system wattage, mmm I'll do a brain drain and if I think of some brilliant and simple way to do it I'll post it. Showing the wattage draw in the manner you do is good info it does give a reference point to use. If i remember correctly the first time I saw you using it the system was drawing just over 200 watts the gf 7800 was 397 and this time next year extrapolated we should see 550+ lol.......BigPipe My PC has a side window it's about the size of a 5000 btu window ac unit at wallmart I wonder??????
Well you might not be able to measure the power/current drawn by the Graphics card exactly (Btw, you can measure the current going to the card from the PCI-E or AGP slot by electrically isolating the relevant pin(s) and taking a current reading with a Multimeter; it would be a difficult thing to do -but I've seen it done.) Anyway, I think it would be useful to know how much current is flowing through the Power Connector to the card at least. As for the rest of the system, current/power could be measured in each Rail and we would have a better idea than just measured power drawn at the mains side (where you have to make allowances for PSU efficiency and other losses and is just an indication of the power drawn by the system as a whole). The advantage of Clamp-Meters (Ammeter, Power Meter) is they can measure big currents (as used in PC's) and the circuit doesn't even have to be broken.
I know that. Yet that poses an issue. I don't think you understand how much time we need to actually test and review graphics cards. There are so many factors that need to be tested and explained compared to reviewing cards two years ago that it's almost crazy. That method would cost a huge amount of time and effort to measure AMPs/Wattage and it would be very tricky to do. Bare in mind that over the years we literally tested hundreds of graphics cards. Imagine applying this method on each card tested, it's just not do-able. No, we need to focus on the big picture here. The Wattage used for a graphics card is just a small part of the article, an indication of what a user can expect. We are not a laboratory that is measuring current pin by pin. We present the overview, the indication. And the current method, although not 100% reliable, is the best and closest option we have right now.
