You’re Staring at
1.4 Billion
Transistors
You could fit nearly six Penryns
onto a single GeForce GTX 280
die, although a portion of the
latter part’s massive size can
be attributed to the fact that it’s
manufactured using a 65nm pro-
cess, compared to the Penryn’s
more advanced 45nm process.
Nvidia packs 240 tiny process-
ing cores into this space, plus
32 raster-operation processors,
a host of memory controllers,
and a set of texture processors.
Thread schedulers, the host
interface, and other components
reside in the center of the die.
With technologies like CUDA,
Nvidia is increasingly targeting
general-purpose computing
as a primary application for
its hardware, reducing its
reliance on PC gaming as the
raison d’être for such high-
end GPUs.DIE SHOTNVIDIA’S NEXT-GEN GPU
NVIDIA’S
NVIDIA’SNVIDIA’S
NVIDIA’SNEXT-GEN
GPUNEXT-GEN
GPUGPU
NVIDIA’SNEXT-GENNEXT-GEN
NVIDIA’S
NEXT-GEN
NVIDIA’SGPU
NVIDIA’SGPU
NVIDIA’SNVIDIA’S
NVIDIA’S
NVIDIA’SNVIDIA’S
NEXT-GENNEXT-GENGPUNEXT-GEN
GPUGPU NEXT-GEN
NVIDIA’SGPU
NVIDIA’SNEXT-GEN
GPUNEXT-GEN
GPUGPU
NVIDIA’SGPU
NVIDIA’S56 | MAXIMUMPC | AUG 08 | http://www.maximumpc.com
A signifi cant increase in the number of
raster-operation processors (ROPs) and the
speed at which they operate likely contrib-
utes to the new chip’s impressive perfor-
mance. The 8800 GTX has 24 ROPs and the
9800 GTX has 16, but if the resulting pixels
need to be blended as they’re written to the
frame buff er, those two GPUs require two
clock cycles to complete the operation. The
9800 GTX, therefore, is capable of blending
only eight pixels per clock cycle.
The GTX 280 not only has 32 ROPs but is
also capable of blending pixels at full speed—
so its 32 ROPs can blend 32 pixels per clock
cycle. The GTX 260, which is also capable of
full-speed blending, is outfi tted with 28 ROPs.MEMORY AND CLOCK SPEEDS
GeForce GTX 280 cards will feature a 1GB
frame buff er, and the GPU will access that
memory over an interface that’s a full 512bits wide. AMD’s Radeon 2900 XT, you might
recall, also had a 512-bit memory interface,
but the company dialed back to a 256-bit
interface for the Radeon 3800-series, claiming
that the wider alternative didn’t off er much
of a performance advantage. That was before
Crysis hit the market.
Cards based on the GTX 260 will have
896MB of memory with a 448-bit interface.
Despite the news that AMD will move to
GDDR5 with its next-generation GPUs, Nvidia
is sticking with GDDR3, claiming that the tech-
nology “still has plenty of life in it.” Judging
by the performance of the GTX 280 compared
to the Radeon 3870 X2, which uses GDDR4
memory (albeit half as much and with an
interface half as wide as the GTX 280’s), we’d
have to agree. Nvidia is taking a similar ap-proach to Direct3D 10.1 and Shader Model 4.1:
The GTX 280 and GTX 260 don’t support either.
A stock GTX 280 will run its core at
602MHz while its stream processors hum
along at 1.296GHz. Memory will be clocked at
1.107GHz. The GTX 260 will have stock core,
stream processor, and memory clock speeds of
576MHz, 1.242GHz, and 999MHz, respectively
(what, they couldn’t squeeze out an extra MHz
to reach an even gig?).THE PHYSX CONNECTION
When Nvidia acquired the struggling Ageia,
we were disappointed—but not surprised—to
learn that Nvidia was interested only in the
PhysX soft ware. While it wouldn’t be accurate
to say that Nvidia has orphaned the hard-
ware, the company has no plans to continue
developing the PhysX silicon. What’s more,PROCESSOR CORESPROCESSOR CORESTEXTURE
UNITSTEXTURE
UNITSTEXTURE
UNITSTEXTURE
UNITSRASTER-
OPERATION
PROCESSORSRASTER-
OPERATION
PROCESSORSPROCESSOR
CORESMEMORY CONTROLLERSMEMORY
CONTROLLERS