Low power multi-monitor graphics card(s)

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jamesg
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Low power multi-monitor graphics card(s)

Post by jamesg » Tue Apr 26, 2011 2:27 pm

Can anyone recommend a graphics card for my desktop PC?

I need to drive 3 DVI (single link) monitors and an HDMI projector. I'm currently using two 7600GT cards, but having just upgraded to Sandy Bridge, I'd like something more modern.

I don't play games much, but need good de-interlacing performance for live TV. I'd also like low power consumption - ideally passive cooling, but won't rule out a fan if it's quiet.

Sapphire HD 5670 Flex was my first choice as it has four outputs, but nowhere stocks it any more. The HD 5770 Flex is too powerful for my needs. Next on my list is two HD 6450 passive cards (9 watts idle each).

Any other recommendations?

Thanks.

CA_Steve
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Re: Low power multi-monitor graphics card(s)

Post by CA_Steve » Tue Apr 26, 2011 6:34 pm

The dirty little secret is when you have 2 or more active monitors on one video card and are idling:
- ATI cards will still idle GPU clock, but memory clock runs full speed. In the 5770, this means an extra 30W. ATI claims this is for system stability.
- I've heard NVidia is worse and doesn't downclock the GPU. Need confirmation from a user.
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fumino
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Re: Low power multi-monitor graphics card(s)

Post by fumino » Wed Apr 27, 2011 4:36 am

CA_Steve wrote:The dirty little secret is when you have 2 or more active monitors on one video card and are idling:
- ATI cards will still idle GPU clock, but memory clock runs full speed. In the 5770, this means an extra 30W. ATI claims this is for system stability.
- I've heard NVidia is worse and doesn't downclock the GPU. Need confirmation from a user.
ive heard this from a few places as well. worth taking into consideration.

i'd probably lean towards the two 6450s that you pointed to in your first post. two lower power cards should be a very efficient solution.
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alecmg
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Re: Low power multi-monitor graphics card(s)

Post by alecmg » Wed Apr 27, 2011 4:52 am

5770 I had, and my current 6950 would enter "video playback" clocks when two monitors were connected. Clocks are less than 3d, but voltage is same, so power consumption was significantlymore than idle clocks.

I countered this with custom downclock profile in Ati tray tools, forcing 2d clocks. No stability issues. Power is down as supposed to be
[size=75]#6) Plug in one device at a time, stick your fingers in your ears, close your eyes, and hit the power switch with a toe[/size]

tim851
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Re: Low power multi-monitor graphics card(s)

Post by tim851 » Wed Apr 27, 2011 5:32 am

http://ht4u.net/reviews/2011/amd_radeon ... ndex10.php (scroll down, second chart)

Ht4u.net frequently measure multi-monitor power draw of graphics cards.
Als Grund dafür nannte uns AMD, dass es im Betrieb mit mehr als einem Monitor zum Bildflackern kommen kann, wenn man den Speichertakt von GDDR5 absenkt
English: According to AMD, the reason is that while operating more than one monitor flickering can occur, when the clock speed of GDDR5 is lowered.

djkest
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Re: Low power multi-monitor graphics card(s)

Post by djkest » Wed Apr 27, 2011 5:39 am

The 5770 is a good card- there is also the 5750 which is a downclocked version- might have the same inputs and is getting pretty cheap now, too!

Also I don't recall from the recent review but what about the 6570 and 6670 cards that SPCR reviewed? The newest gen cards are remarkably efficient and pretty future-proof with great DX11 implementation.

CA_Steve
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Re: Low power multi-monitor graphics card(s)

Post by CA_Steve » Wed Apr 27, 2011 6:31 am

For HTPC use, the 6570 and 6670 may be better than the 6450 with HQV scores of 201. The differences are in noise and artifact reduction and the adaptive processing tests.
Tom's provides HQV 2.0 benchmarks

Anandtech says the 6450 is about the same as the 5570 with a score of 188. Then goes on to say the scoring is subjective. Unfortunately, Ganesh has gone into hiding, so no comprehensive testing at Anandtech for the 6xxx.

Perhaps one 6450 and one 6570 (for the projector) will work for you. Gaming opens this up to another conversation: what types of games, what resolution, do you want all the bells and whistles?...
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dhanson865
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Re: Low power multi-monitor graphics card(s)

Post by dhanson865 » Wed Apr 27, 2011 7:00 am

jamesg wrote:Can anyone recommend a graphics card for my desktop PC?

I need to drive 3 DVI (single link) monitors and an HDMI projector. I'm currently using two 7600GT cards, but having just upgraded to Sandy Bridge, I'd like something more modern.

I don't play games much, but need good de-interlacing performance for live TV. I'd also like low power consumption - ideally passive cooling, but won't rule out a fan if it's quiet.

Sapphire HD 5670 Flex was my first choice as it has four outputs, but nowhere stocks it any more. The HD 5770 Flex is too powerful for my needs. Next on my list is two HD 6450 passive cards (9 watts idle each).

Any other recommendations?

Thanks.
Keep in mind a single 5770 or lower won't drive 4 digital DVI/HDMI displays on it's own. You'd have to buy Displayport to DVI adapter(s) (and/or a displayport hub) to get 4 digital non display port outputs.

On a traditional 5xxx card you'd be limited to 2 digital DVI/HDMI displays without adapters. On the 5670 Flex that goes up to 3 without adapters.

So if you really want to use all 3 monitors and the HDMI projector without physically switching cables around in-between using one or the other you'll want 2 video cards or you'll want to buy some displayport monitors. Definitely cheaper to just buy a second low end card.

Looking at the table in my post at viewtopic.php?f=13&t=62126&p=539956#p539956 the 5450 and 6450 are the low power options. Just be sure to get the DDR3 version of the 6450 if you go that way as the GDDR5 version uses more power.

If you aren't in a hurry you might wait for the PowerColor Go! Green HD6450 1GB DDR3 HDMI Part NumberAX6450 1GBk3-SH to be in stock as it'll probably draw less power than other 6450 designs and will be a higher quality card. If you are in a hurry you can just go for the Sapphire fanless 6450 or ASUS fanless 6450. They are all right at the $50 price level so getting two 6450 cards is cheaper than any higher card + adapters/hubs.

edit: and what CA_Steve said. many questions left to be answered. Of course if you are willing to experiment you could order a single 6450 to try out and see if you like the quality and then decide on a 6570 or 2nd 6450 to add afterwards.
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jamesg
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Re: Low power multi-monitor graphics card(s)

Post by jamesg » Mon May 09, 2011 12:41 pm

Thanks all for the great advice. I fitted two Sapphire HD6450 512MB DDR3 (passive) cards today. Just did some quick tests and they are using about 15 watts less on idle than my two Nvidia 7600GT cards.

Only slight annoyance is that they have DVI and HDMI ports very close together, so an HDMI to DVI adapter doesn't quite fit. I'll have to buy another cable instead.

Idle temps seem to be around 50-60 deg C.

Memory and GPU clocks are different on each card (they have different numbers of monitors connected). I'll check this when I have the monitors set up properly.

For anyone that's interested, I ran Windows Experience Index:

Nvidia 7600GT
Graphics: 5.9
Gaming Graphics: 5.4

HD6450 DDR3
Graphics: 4.6
Gaming Graphics: 6.1

I haven't looked at image quality yet.

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