NVIDIA's GeForce 400M Mobile GPUs: 7 New Fermis Introduced

Author: Michael "SKYMTL" Hoenig
Date: September 2, 2010
Product Name: NVIDIA GeForce 400M
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400M-Series TDP: An Explanation & Our Findings

Before we go any further here, let’s state one thing: NVIDIA doesn’t discuss power consumption or TDP of their mobile parts with the press. Or so we’ve been told. Nonetheless, as you can see in the charts below we have dug up many of the TDP numbers NVIDIA gives to system integrators. There is however an explanation that needs to go along with them in order for you to better understand how these numbers are calculated.

To begin with, TDP does NOT equate power consumption so please put that thought to rest once and for all. TDP (thermal design power) is a number given in watts which acts as a guide that allows system integrators to properly design cooling solutions for a given product. Basically, it tells SIs how much heat will be produced and as such, they can configure a chassis and heatsink combination which will effectively keep thermals within acceptable boundaries.

GTX 480M GPU + MXM Module

When it comes to mobile parts, things get even more complicated. In many cases, higher-end graphics cards are integrated into laptops using Mobile PCI Express Modules (MXM for short) which means they can be changed out due to their use of a standardized installation format. These modules act much like the add-in cards we are used to seeing in the desktop market and incorporate the memory and power distribution for the GPU. On the other hand, some vendors integrate the GPU directly onto their motherboard PCB which eliminates the need for a stand-alone module.

The issue with TDP and even power consumption figures in the mobile GPU market is that some include the MXM module in their calculations while others only indicate the power consumption / TDP of the GPU core itself. Naturally, these two numbers will be at odds with one another since the addition of the MXM module will increase heat production as well as power needs. As such, the numbers you see below are the TDP of ONLY THE GPU CORE. Typically, the addition of an MXM module can add anywhere from 10W to 30W more heat to a mobile GPU.

As you can see, the TDPs of the NVIDIA cards are relatively similar to those seen on the ATI side of the fence except when you get into the ultra high end segment where the GTX 480M is the only contender. Remember, the GTX 460M / GTX 470M are meant to compete directly with the HD 5870 so things look quite even here. However, these numbers do not take the MXM modules into account and we already know that the 2GB module the GTX 480 uses pushes it’s TDP close to the 100W mark.

All in all, it looks like NVIDIA has managed to keep the heat production of their Fermi-based mobile parts well within reason if you look below the GTX 480M. How these parts stand up to the competition in performance is another matter altogether though.

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