XFX GeForce 8800 GTX and eVGA 8800 GTS GPU’sWed, Nov 08, 2006 - 12:00 AM
XFX 8800 GTX
Our 8800 GTX was provided by XFX and is actually their only model since there are no overclocked cards scheduled at this time.
This is one monster of a card both in performance and physical size. One of the reasons for the incredible size of the card is the 768MB of GDDR3 memory parked around the GPU. Finding room for all those chips and their traces require the additional real-estate. The second and most obvious reason is the sheer size of the GPU itself. At 681 million transistors it is now the transistor king. Not even the mighty Intel Core 2 Duo with 2 CPU?s and large cache has that transistor count! The length of the PCB is 11.5″ with the overall length of the entire graphics card just breaking 12″ when the mounting bracket is included. It?s hard to believe but it?s now important to know how much room you?ve got inside your case to install this card. I was able to successfully install the 8800 GTX in an Antec Sonata II with just a little maneuvering.
Here we have the two PCI-E power connectors that the GTX requires for operation. You’ll need a 450W power supply with a 12v rating of 30A to run one of these beasts. If you’re thinking of a pair of these in SLI, 750W looks to be the starting point.
With the heat spreader removed one can see what is under the card and just for fun we put the Intel Core 2 Duo E6700 that was featured in our Intel Core 2 Duo IHS removal article on top to show that the IHS on the G80 core is much larger than conroe.
The smaller chip on the board looks like an older Athlon XP, but in reality it’s the RAMDAC chip. It provides dual 400MHz RAMDAC and Dual – Dual Link DVI output, TV Out and HDCP. NVIDIA calls this the External Video I/O Chip or simply External RAMDAC, so it’s called a number of different names. The RAMDAC has been part of the chip for generations, but was moved off the GPU core on the G80 due to noise levels.
Here is the new core……..even though the core size is gigantic NVIDIA is still able to get a great clock speed of 575MHz. This is only 75MHz shy of the tiny G71 core. The core of 8800 GTX is still manufactured on the same TSMC 90nm process as the 7900 series and most of ATI?s X1000 series so the speed is very impressive for a core of its size. Although the fixed function speed for most parts of the core is 575MHz the stream processors are pumped up running at 1.35GHz.
While some may question the use of GDDR3, the 768MB of memory runs at a still impressive speed of 1.8GHz and is no doubt cheaper and in greater supply than GDDR4. The memory controller of G80 is capable of using GDDR4 and it?s likely we?ll see that in the future once NVIDIA moves to a 65nm process.