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XFX GeForce 7800 GS XT Edition - An AGP Upgrade

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Manufacturer: XFX
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Introducing the NVIDIA 7800 GS

Introduction


It has been more than a year since our last AGP graphics card review: the NVIDIA 6600 GT.  It has been even longer since we have seen a high end GPU released in an AGP format, and because of that I basically assumed, as did most users, that AGP was dead and gone.  NVIDIA had second thoughts on this though, and decided to take one more stab at an AGP part.


And it makes sense; there is a large group of users out there that still have AGP motherboards and platforms that may not plan on upgrading to the new PCI Express based systems any time soon. 


The NVIDIA GeForce 7800 GS


The GeForce 7800 GS GPU should be very familiar to anyone that has read our other G70-based product reviews.  Since the initial launch of the 7800 GTX NVIDIA has been making slight changes and modifications to the core to place it in different market segments. 



































 


7800 GTX


7800 GT


7800 GS


Core Clock


430 MHz


400 MHz


375 MHz


Memory Clock


1.2 GHz


1.00 GHz


1.2 GHz


Pixel Pipes


24


20


16


Vertex Pipes


8


7


6


Memory


256 MB


256 MB


256 MB


The table above tells the majority of the story here.  The 7800 GT (that was only a PCI Express based part) took 4 pixel pipes (a single pixel quad) and a single vertex pipe off of the GTX model, lowered the clocks and lowered the price.  The 7800 GS follows a similar patter: take 8 pixel pipes (two pixel quads) and 2 vertex pipes off of the GTX model, lower the clocks and lower the price.  With lower clocks and fewer pipelines for processing, this obviously means slightly lower performance, but it should still be a big upgrade over anything else available on the AGP side from NVIDIA. 



The 7800 GS is still based on the 110 nm process with about 302 million transistors according to NVIDIA.  The memory bus is still 256-bits wide and the cards default memory configuration comes with 256 MB for a total memory bandwidth of 38.4 GB/s.  You can tell by looking at the picture above that the 7800 GS isn't significantly smaller than the GTX or GT so the part won't be as cheap as the 6800 GS, but it still should be lower than current PCIe based cards.



This block demonstrates the beauty of a modulate architecture.  This is essentially the same diagram we saw here in our GTX review.  Besides the afforementioned vertex and pixel pipes, the new 7800 GS also has a deficit in ROPs.  Where as the 7800 GTX had 16, the GS will only sport 8 of them.  This cuts down on the fill rate considerably, but we'll see in our testing if this will influence our benchmarks.  

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