Re: Video Cards, Advise and Going Wacky

["Dave Emmerson" <dave@xitroneurope.com>]

Hi Charles,

[snip]

>Dave Emmerson wrote:
>FWIW, I found dual-head Matrox cards to be totally incompatible with the
>rest of my custom system (no on-board video), repeatedly freezing it solid
>after an hour's use. I'd taken care to keep the area around the boards'
>cooling fans clear, and the inside of the case was cool. I eventually
binned
>them in disgust and bought cheaper ATI cards which have been perfectly
>adequate. Your mileage may vary. D.

< To me, freezing after an hour's use suggests heat -- in an hour the card
should have repeated everything that might give it indigestion many times,
but some low-current components can take that long to get up to working
temperature.

My thoughts exactly :-)

< Your spec suggests you have up to 4 PCI cards installed, so you might be
obstructing/diverting the airflow *just* enough to affect cooling.

Possibly. One of the SCSI adapters I work with will only work as a 'bus
master', which means I normally use slot 1 for all SCSI cards. But I was
using a Syquest in the bottom slot at that time.

< With present-day motherboards, I never use PCI slot 1 if there's an AGP
card installed.
<
< Rather than use it, I'd look for a motherboard with more slots...
<
< Two reasons -- a card in slot 1 effectively blocks off the AGP fan, and
the AGP slot and PCI-1 are on the same bus (slot-1 is where you'd normally
stick a PCI video card in the absence of AGP), so that using it may well
upset the video -- and often does...

It's where the ATI card now sits :-)

< If slot 1 is empty, see if you can arrange a definite airflow across the
video card from outside (maybe an 80mm fan in the front of the case, if
there's no provision for one below the power supply at the rear) -- you may
well have an area where the airflow is pretty dead, and the AGP fan
recirculates the already warmed air.

As this is a development PC (board changes every week or 2), it often runs
with the left hand panel removed, and a 12 inch oscillating room fan blowing
into the case. I think the skinny fan on the Matrox card just wasn't up to
the job, the heatsink was certainly quite hot, rather than just warm.

< This is why AMD now want power supplies to have a bottom air intake --
motherboards almost universally have the CPU directly beneath it, and
without something to keep it flowing the air just goes round and around in
the sheltered corner between the video card and the power supply.

The PSU fan should be dragging air out of the case, and I can't recall
building a tower system which didn't have vent holes in that side of the PSU
case, so I'd not have had that problem. I guess my supplier just hapens to
stock a good brand. Their 'AMD approved' ones are quite recent, and are
described as 'low noise' (electrical, I imagine, rather than acoustic).

< You probably also find the system quite picky about where you put the SCSI
card?

Hmm I'm not sure about this particular system, I think it only barfs if I
use 2 different Adaptec controllers. Some MB's only support bus mastering in
slot 1, so if I can't be choosy about which MB or SCSI adapter I'm using,
that's where it usually goes. But much of the time I'm working on stuff like
Epson 10000 drivers, so may not have a SCSI card fitted in this system at
all.

Thanks for your input, but we seem to think alike :-)
What puzzles me is that I had 2 slightly different Matrox boards (I took it
back and got it replaced with a similar model once), but both failed the
same way. PnP said there were no conflicts, and there are no non-PnP boards.
I took out the working sound card (and even tried without the modem and
network cards for a while) to ensure there was at least one IRQ free, and
both the old and new ATI cards have been quite happy in the same system. The
decider for me was the heatsink temperature, but if this was a common
failure, I'd have heard about it, I'm sure. My previous experiences with
Matrox boards had both been problem-free.

D.


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