Technical data

is experiencing something of a revival with the
help of NVIDIA.The new interface allows for sev-
eral x16 PEG (PCI Express for Graphics) slots on
one board.The success of NVIDIA’s SLI technolo-
gy will depend mostly on the pricing and the avail-
ability of motherboards with the appropriate sup-
port. So far, SLI capability has been announced for
PCI Express versions of the GeForce 6800 Ultra,
6800 GT and 6600 GT cards.You can read up on
SLI here: http://graphics.tomshardware.com/graph-
ic/20040628/index.html.
Power Requirements
Modern graphics processors are very complex; the
newest flagship models contain more than 200 mil-
lion transistors. Currently, the record for most tran-
sistors in a consumer graphics chip is held by
NVIDIA’s GeForce 6800 GT and Ultra chips,
which weigh in at 220 million transistors.To give
you a frame of reference, bear in mind that even
Intel’s Pentium 4 EE CPU consists of "only" 178
million transistors – 149 million of which make
up the second level cache!
The hunger for power of modern graphics
cards is correspondingly high, and can no longer
be satisfied through the current supplied through
the AGP slot alone.While the AGP slot supplies
up to 45 watts, a GeForce 6800 Ultra draws up to
110 watts under full load. To make up for the dif-
ference, 2 additional ATX Molex connectors
need to be plugged into the card.This is an
extreme example, and most cards need only one
such auxiliary power plug.The new PCI Express
interface improves this situation by offer-
ing up to 75 watts, but even this obvious-
ly isn’t enough for the highest-end cards.
The way the auxiliary power cables are
split up is important.Whenever possible,
the graphics card should always have its
own, unshared cable. The only other
component that can be attached to the
same cable without risking trouble is a
case fan.
Depending on the power requirements
of a card, the power supplied by the
motherboard may not be enough. In this
case, cards require auxiliary power con-
nectors fed directly by the system’s power
supply.This picture shows the types of
connectors currently in use.
In 2D mode, graphics cards draw comparatively
little power. However, in a 3D game that puts a lot
of stress on the graphics card, the CPU and poten-
tially even the hard drive, the power draw can peak
quite suddenly and overwhelm the PSU.The
unavoidable consequence is a crash of the entire
system.
As a reaction to the power needs of their cards,
both ATI and NVIDIA state minimum require-
ments for power supplies. However, these should
only be considered guidelines, at best, since the
power supply also needs to power the CPU, the
drives and every other component in the system.
The power requirements quoted by the manufac-
turers refer to a standard PC with a modern CPU,
say a Pentium 4 3.2GHz, a hard drive, a DVD drive
and a soundcard. If your computer houses more
THG Graphics Card
Buyers Guide
21