Power Consumption--Graphics Cards And Electricity Costs
In the following tables, the consumption of the test system was subtracted from the overall total to yield the approximate power consumption of the graphics card. The actual values fluctuate depending on the performance class of 3D graphics chips, which is why we made our calculations with average values. Note that for SLI with Nvidia graphics cards, the nForce 780i chipset from Nvidia is used; this component requires about 50 watts more than the X38 chipset from Intel.
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Test System
2D Without Load
3D Full Load
2D Average
3D Average
X38 Chipset
52-68 Watts
80-120 Watts
64 Watts
104 Watts
780i Chipset
114-125 Watts
142-158 Watts
119 Watts
150 Watts
Again, this measurement was made at the outlet, and serves only as a basis for the calculation of the electricity cost. As examples, the 2D operation was estimated with both 8 and 24 hours a day and the 3D operation with 8 hours daily use. The power cost was estimated at 20 cents per kilowatt-hour (kWh).
With the GeForce GTX 260 and 280, you can easily see how the new graphics chips slow down in 2D mode—the older GeForce 8800 Ultra running 8 hours a day uses up almost double the electricity. The cost of a double-chip card (Radeon HD 4870 X2) is pretty intense; if you let the PC run on the desktop for two years continuously, the electricity cost adds up to the purchase price of the card.
If you compare the Radeon HD 4870 X2 and HD 4870 Crossfire, you can easily see that you could save up to 20 watts per HD 4870 card in 2D mode, if only AMD clocked down the single chip card as well. Generally, you should not use a double-chip card, SLI or CrossFire for a computer to remain in use 24 hours a day—a more modest graphics solution can reduce the electricity cost by at least 50%.
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This article was due. No more you need an 800 watt psu for the 4870 , core2 quad ad 1 hard drive anymore :p
Guest11since Core i7 920 has TDP = 130W, how can it consume 85W only?The TDP is more of a design thing. Almost all of Intels initial Core2 line had a TDP of 65 watts yet many took much less power. Intel gives a worst case of that type number and does not measure every cpu.
AMD does the same thing. They listed almost all the initial Athlon 64's at 89 watts yet many did not take that or give off that amount.
zxv9511.21 Jigawatts !!!You act like you would need a small fusion reactor or maybe a bolt of lightning to get that?
So my system actually has a too big power supply to be effective?
I'm running a 3,4ghz c2d with 5x500gb sata drives, a dvdrw and a 4870 on a p35 board.
According to the article that's not going to draw the ~400W needed to get within effective range of my corsair 620 ....
The TDP (thermal design power) is meant to be a guideline for the cooling solution, not the power consumption. To qualify for a cpu with a TDP of 120W, a cooler must be able to dissipate 120W. Practically, of course, this means it is an upper bound to (sensible) power consumption.
also small note: Is it just me or is it strange to see the 260 SLI consume more than the 280 SLI. maybe in need of a beefier test scene...
better off with too much power supply than not enough. at least if you over-spec the power supply you leave some breathing room for any additional components.
