LeeG said:
I am looking to upgrade to a athlon 64 x2 with dual pci x16 slots for two
graphics cards. My question is this.
What psu will be suitable for this setup and do the graphics cards need to
be the same chipset ie 2 7300 nvidia 256MB or can they be any cards.
IF I have posted this in the wrong place my apologies and can someone point
me in the right direction
Another group you could post in, would be -
alt.comp.periphs.videocards.nvidia
Generally, it is best if you use matching cards. But I'm not up on the
latest rules, as at least some of the rules are artificially imposed
by the drivers (may not be completely justifiable technically). For
example, some day, Nvidia may decide to allow motherboards with Intel
chipsets to run SLI mode. But not as of today. Nvidia allows SLI if
the motherboard has an Nvidia chipset. Or if an Nvidia PCI Express
switching chip is being used (such as on an Nvidia dual GPU video card
like a 'GX2 type).
Also, we should be clear on what you're trying to do. If you install
two video cards, with two connectors on each card, and wish to drive
four monitors for non-gaming purposes, then there are no restrictions
on that. That is not SLI, if four monitors are being driven.
SLI mode, is a mode that allows the 3D gaming power of two identical GPUs
to be combined, in the driving of just one monitor. For example, if each
GPU worked on half the image, or the GPUs alternated frames, you could see
that there is "parallelism" in that model. It allows the combining
of the power of the video cards. But each potential operating mode,
has its efficiencies or inefficiencies, so two cards doesn't necessarily
give a doubling of performance. In some cases, in fact, for a given game,
there might be no net improvement seen for a game at all. Performance
improvements vary from one game to the next. This is why the SLI
drivers come with "profiles", which represent the best choices for
a list of games. If your game is on the list, it means Nvidia thought
about how best to run it under SLI.
In terms of infrastructure, higher end video cards use a connector and
flex cable, that runs between the two cards. That is how the cards
communicate, and combine their SLI power. It is also possible to
send the same kind of information via the PCI Express bus, so some
cards have no SLI connector on the top edge of the video card. And
the driver understands that, and uses the PCI Express bus to carry
the data.
As for "7300", there are different models.
http://www.gpureview.com/videocards.php
The 7300 GS here is 16.1 watts. Even if the card happened to be double
that power, or 32 watts, the power could all safely be provided through
the PCI Express slot connector, without needing a 2x3 PCI Express aux
connector on the end of the video card. (A safe limit used by video
card designers, is about 12V @ 4A, before the 2x3 connector is needed,
so some 48W cards run using power just from the slot itself.)
http://www.xbitlabs.com/articles/video/display/power-noise_7.html#sect1
In terms of power consuming items, a high end processor might use 125W.
If the Vcore converter is 90% efficient, that is 139W drawn from the
power supply. Add a couple 32 watt video cards, brings the power to 203W.
Add 50W for motherboard and RAM. 6W for fans. 13W for hard drive.
25.5W for a CD drive. 10W for standby power. Now the total is 308W.
It should not take a large supply, to do the job. For comfort, and so
you can reuse the supply in the future, you might look for a 450W to
500W supply. That should be plenty. There are different qualities of
power supplies on the market, and if you insist on one costing <$20,
then a "500W" of that type, might only be capable of 300W anyway.
For a list of brands to avoid (now out of date), avoid anything listed
in "Tier 5" here. Some companies make good and bad models, and so the
company in question could appear in multiple tiers. With a list like
this, you can easily avoid "Deer" or "Powmax"
http://www.xtremesystems.org/forums/showthread.php?t=108088
A picture of a Powmax, from the Newegg site
I think they wanted
the customers to have nightmares, and turn off the supply at the
end of the day
http://c1.neweggimages.com/NeweggImage/productimage/17-163-018-06.JPG
HTH,
Paul
