Power Consumption and Performance per Watt

Testing power consumption was done by testing idle power at the desktop and testing load while running 3DMark06 at 2560×1600. 

NVIDIA GeForce 8800 GTX Review - DX10 and Unified Architecture - Graphics Cards 107

Okay, so with all that performance, it had to come from somewhere right?  The GeForce 8800 GTX does use more power than the competing cards here, even the dual-GPU 7950 GX2 card.  But, it doesn’t seem to be to the proportion I was originally expecting during all the rumors of G80 from months ago.  What happened to the required water cooling and 1 kW PSUs?  NVIDIA either scaled back the part because they didn’t need any more performance (as our benchmarks show) or came to their senses on that. 

After all, we’re only talking about a 12% increase over the 7950 GX2 and about 24% over the 7900 GTX and X1950 XTX.

Looking at Performance per Watt

Speaking of power consumption, and the enevitable complaints of ever increase power requirements, I decided taking a quick look at the performance per watt of these parts might be interesting.  Let’s see what we can find by simply taking the load power levels from each card and looking at their watts per frame rating…yes I just made that up.

2560×1600

BF2

CoD2

FEAR

Lost Coast

Prey

3DMark06

NV 8800 GTX

3.25

9.09

8.56

5.00

5.59

2.7

NV 7950 GX2

4.10

11.02

11.71

7.03

11.21

3.0

NV 7900 GTX

5.26

13.58

13.90

8.57

8.76

3.6

ATI X1950 XTX

3.69

10.54

8.11

7.34

6.20

3.4

Okay, so was all that work setting up this table completely useless?  Maybe.  But we are able to see that though the power consumption is higher on the GeForce 8800 GTX than the other cards, in all but one test, the performance gains out weigh the additional power used.  That means not only is the 8800 GTX a better performer, but it is more efficient as well.  The only exception is FEAR, where at 2560×1600, the ATI X1950 XTX sneaks in a win on the performance / watt measurement, though the 8800 GTX is still a better performer in the game.

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