NVIDIA GeForce FX 5950 Ultra
This was the top-end model from NVIDIA’s last generation of graphics processors. It is made with 0.13-micron technology and consists of about 135 million transistors. MSI supplied us their graphics card on this GPU called FX5950 Ultra-VTD256:
The card copies the reference design, although this is hardly visible for the massive cooling system, which consists of a cooler than covers the GPU and the face-side memory chips, and another cooler with heatsinks that cover the PCB surface and the memory chips at the back side.
The nominal frequencies of the card are 475/950MHz in the 3D mode and 300/950MHz in 2D. So, although 475/950MHz frequencies are shown in the diagram, the results in the Idle mode correspond to 300/950MHz clock rates. The card (or rather, the driver) controls the frequencies and there’d no sense in my interfering.
Here are the results of my tests:
Here is the second surprise to you! The GeForce FX 5950 Ultra has the highest power consumption among all the tested graphics cards, with GPUs both from NVIDIA and ATI, in the Burn mode!
This result is indicative of what price NVIDIA had to pay to set so high a clock rate. Under a load, this graphics card eats more power even than the GeForce 6800 Ultra, which delivers an incomparably higher performance. Note also that the GeForce FX 5950 Ultra consumes less power in the Idle mode than the 6800 Ultra – unlike the new-generation chips, it just drops the clock rate and the voltage of the GPU when idle.
The GPU voltage regulator on GeForce FX 5950 Ultra graphics cards can adjust the output voltage at the driver’s request – it is lifted up in 3D and reduced in 2D applications. If the core is too hot, the voltage and frequency of the graphics processor are reduced to an in-between value – the so-called Low Power 3D mode is activated.
According to RivaTuner, the version 61.24 Detonator sets a 2D voltage of 1.2v and a 3D voltage of 1.5v for the GeForce 5950 Ultra. The real voltages on the MSI card were 1.217v and 1.577v, as my measurements showed.
So, the GeForce FX 5950 Ultra needs more power than the GeForce 6800 Ultra. Why then was there no clamor about PSUs to use such graphics cards with? Let’s examine the detailed picture:
Unlike graphics cards with GeForce 6 series chips, the GeForce FX 5950 Ultra distributes the power load among the power circuitry more evenly and uses the +12v line sparingly since it is traditionally overloaded with other system components. In the Burn mode, the currents on the 12v, 5v and 3v lines of the AGP slot are 4.92amp, 2.29amp and 5.59amp. The highest current is on the 3.3v line, which is usually least loaded of all.
A remarkable fact: the current in the 3.3v line approaches the maximum acceptable value as stated in the AGP specification – 6 amperes. At overclocking I even exceeded this limit, hitting 6.05 amperes. However, this shouldn’t worry you too much – I haven’t heard yet any users reporting problems related to the power limit of the AGP slot.