2 different GPUs in 1 system.

[Ahielia]

I'm most likely going to buy a 560 Ti in this next month (EVGA 2GB), and while I do not need the horsepower from 2 cards, I was thinking about still using my good old 275 GTX as a PhysX slave.

I read through both the SLI and PhysX faqs on Nvidia's home page, but I couldn't find an answer (that I understood ) to my questions.


1) The GTX will only do PhysX, nothing else?
2) The GTX requires 2x 6pin power connectors to function properly, does it need those when it's not the primary gpu?

[Hatorijr]

if you have 2 different nvidia cards than you can dedicate one as the dedicated physx card and the other as the main rendering card. but for the cards to all function properly, you must properly supply power to them so you need to have all the connections to the card so that it has the power that it requires.

[SCHUMI_4EVER]

Yes to both questions as far as I know.

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[Princess Garnet]

Unless you're playing alot of games that benefit greatly from a dedicated PhysX card (I can probably count them on one hand, Batman Arkham Asylum, Mafia II, maybe some others...), then in my opinion, it's not even worth the heat and power required that comes with the extra card sitting there. It will idle wasted most of the time. I did the same thing with my GeForce 8800GT and decided it wasn't worth it full time.

Make sure your PSU has the connectors (and the power) to drive both cards.

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[niku]

**** this can be done? I thought you needed two cards of the same type to run sli.
So if I buy a 460 now can I use my old 8600gt with it on sli?

__________________

[Princess Garnet]

He's not asking about SLi. He's asking about using a single GPU for rendering, and offloading the PhysX computing to a separate GPU. That can be done with two GPUs of different type. SLi does require the GPUs to be the same.

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[Phil]

A second videocard would be good for a 3 monitor setup as well.

[Ahielia]

Originally Posted by niku

**** this can be done? I thought you needed two cards of the same type to run sli.
So if I buy a 460 now can I use my old 8600gt with it on sli?

You can use the 8600GT as a PhysX renderer, yes, but not SLI. SLI requires 2 identical cards (different clock speeds and manufacturers work)

Like Nvidia says in their FAQ:

Originally Posted by Nvidia

Can I mix and match graphics cards that have different GPUs?
- No. For example, an XXXGT cannot be paired with a XXXGTX in an SLI configuration.

Can I mix and match graphics cards from different manufacturers?
- Using 180 or later graphics drivers, NVIDIA graphics cards from different manufacturers can be used together in an SLI configuration. For example, a GeForce XXXGT from manufacturer ABC can be matched with a GeForce XXXGT from manufacturer XYZ.

Can I mix and match graphics cards is one of them is overclocked by the manufacturer?
- Yes. A GeForce XXXX GTX that is overclocked can be mixed with a standard clocked GeForce XXXX GTX.

Can I mix and match graphics cards with different sizes of memory?
- No. For example, an XXXGT 512MB cannot be paired with a XXXGT 1GB in an SLI configuration.

------------------------------------------------------------------------

I did find an interesting article from less than a year ago, and the numbers from a dedicated card was a bit surprising, especially with the switchover.

Originally Posted by Garnet

Make sure your PSU has the connectors (and the power) to drive both cards.

(APS-650C)

On closer inspection of both the PSU and the cords I got lying around, I actually don't have enough connectors at the moment, but I do if I disconnect some drives
While the PSU doesn't have 4x 6-pin connectors, I do have 2 conversion cables (2x4pin to 6pin).

Attached Images

A135seriesSpec01.gif (127.0 KB, 71 views)

[niku]

So I can use two different cards and not connect the sli bridge and there after use one card for physics and other for graphics?

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[Ahielia]

Exactly.

That way, the primary card will have more spare processing power to use for graphics.

[Hatorijr]

you do not always need the full set of connectors, and in my case i doubt any psu would, thats why they sometimes include converters for you to use but when doing that, you must take care to make sure your psu has the power available to handle the load.

but keep in mind, that when using multiple cards that i believe its the north bridge(was in my case) will start heating up pretty bad so you need to keep an eye on that to make sure your system does not overheat, because it may not be the video cards that do overheat but something else as a result of multiple cards being used.

[Princess Garnet]

Originally Posted by Ahielia

(APS-650C)

Specs alone say only so much, although I will say that's quite an unusual distribution of power there (an even 25A on all rails). It looks alright though. Looking it up, it's Chieftec, which I have little run in with (seems it's more popular in Europe), so I can't say. Doing some quick searching shows up possible OEMs as Sirtec and Delta depending on the PSU. The latter is generally poor and seems to have them a bad reputation, but Delta is very very solid (Dell even uses them). If that's a Delta, I'd definitely trust it. The 650W model you have seems to be Delta. I'm finding no reviews on that model, but it seems trustable given that.

With that type of rail distribution and lack of cables though, be careful. If possible, and you use an adapter, connect each of the two molex plugs into separate bundles coming from the PSU. This prevents the entire load from being carried through one set of wires. It probably won't melt otherwise, but it's a recommendation I'd try and follow.

Likewise, 25A is 300W on a 12V rail, so those two cards, plus others if they happen to be on the same rail, could trip that, so you may need to experiment on where you draw power from for the secondary card. It should be okay though since I don't think it'll draw a whole lot just doing PhysX, but I don't know.

Originally Posted by niku

So I can use two different cards and not connect the sli bridge and there after use one card for physics and other for graphics?

Yes, you can do that.

You don't need an SLi bridge if you're not running SLi (even then it's not always required, per se).

Originally Posted by Ahielia

That way, the primary card will have more spare processing power to use for graphics.

Yes, but sometimes the primary rendering card can take care of the rendering and the PhysX faster. Pairing a GeForce GTX 275 for PhysX along with a GeForce GTX 560 Ti for rendering, this should be fine, but I wouldn't pair a GeForce 8600GT with it (unless the rendering card is like a GeForce 8800GT or something). Think of as the second card bottlenecking in the case.

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[lagunareturns]

Originally Posted by Ahielia

I'm most likely going to buy a 560 Ti in this next month (EVGA 2GB), and while I do not need the horsepower from 2 cards, I was thinking about still using my good old 275 GTX as a PhysX slave.

I read through both the SLI and PhysX faqs on Nvidia's home page, but I couldn't find an answer (that I understood ) to my questions.


1) The GTX will only do PhysX, nothing else?
2) The GTX requires 2x 6pin power connectors to function properly, does it need those when it's not the primary gpu?

Here are the definitive answers:
1) Both or any one card can do physx or you can choose the cpu to handle the task, it even doesn't even need to be in sli, just go to nvidia control panel and you can make your choice

2) The power connectors are needed, well since some rare motherboards can offer more power to video cards meaning yes the video card will display without the power connectors, still expect a ton of blue screen of death....

It is easy that card does need the power to function, without the power then it wont simply work, also the 275 gtx definitely wont work at all as it does require the power to function

[Princess Garnet]

Originally Posted by lagunareturns

1) Both or any one card can do physx or you can choose the cpu to handle the task, it even doesn't even need to be in sli, just go to nvidia control panel and you can make your choice

2) The power connectors are needed, well since some rare motherboards can offer more power to video cards meaning yes the video card will display without the power connectors, still expect a ton of blue screen of death....

For the first one, in this case, both can't do PhysX. This isn't an SLi setup. It's two separate GPUs. In this case, if he wants to utilize both GPUs, he will be forced to dedicate one to rendering, and dedicate the other to PhysX, for two separate GPUs. He can't have both do PhysX. I'm pretty sure with a dedicated PhysX processing unit, the primary GPU does no PhysX at all (that is, afterall, the point).

For the second, which motherboards are that? I'm pretty sure it's a limitation of the PCI Express slot itself of 75W. I don't think any can allow more. That's what the connectors are for. Six pin power connectors offer an additional 75W, and eight pin power connectors offer an additional 150W.

Some cards themselves may boot without the power connector plugged in, but some won't (and some have a speaker on them that will beep when attempting to booth without it).

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[Ahielia]

Originally Posted by lagunareturns

or you can choose the cpu to handle the task

That will not be happening

CPU PhysX rendering is horrible at best.

[Princess Garnet]

Of note, in Mafia II, certain PhysX (the cloth PhysX) will be done on the CPU, even if you have an nVidia GPU, if you have PhysX enabled. Only certain PhysX will be accelerated by the GPU. There's workarounds for this (namely, disabling all clothing PhysX but those for the main character and a few secondary ones, so there's not as much), but it still only helps a little. If Mafia II is one of the few games with GPU accelerated PhysX you'll be playing, you do want a dedicated card for PhysX if you so mch as enable it (so for SLi users, this means disabling SLi and dedicating one to PhysX, unless you happen to have a setup that involves SLi plus PhysX, otherwise your SLi setup is wasted while PhysX are done on the CPU).

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[fivefeet8]

I'll probably be putting my 8800gt back in for Batman: Arkham City.

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[lagunareturns]

Originally Posted by Princess Garnet

For the first one, in this case, both can't do PhysX. This isn't an SLi setup. It's two separate GPUs. In this case, if he wants to utilize both GPUs, he will be forced to dedicate one to rendering, and dedicate the other to PhysX, for two separate GPUs. He can't have both do PhysX. I'm pretty sure with a dedicated PhysX processing unit, the primary GPU does no PhysX at all (that is, afterall, the point).

For the second, which motherboards are that? I'm pretty sure it's a limitation of the PCI Express slot itself of 75W. I don't think any can allow more. That's what the connectors are for. Six pin power connectors offer an additional 75W, and eight pin power connectors offer an additional 150W.

Some cards themselves may boot without the power connector plugged in, but some won't (and some have a speaker on them that will beep when attempting to booth without it).

i was able to select two different nvidia video cards (8800gt and 260 gtx) to do sli at the same time and they werent using sli... but they only doing physx together but nothing else to have them doing everything else then sli is needed... also note that while i was able to select the two cards to the processing, once i select the cpu to handle the task both video cards are removed from the selection

[Hatorijr]

because 2 different cards, as stated by multiple people before, can not be used for sli, for actual sli, you must have 2 of the same card, other wise all you can do is select 1 for rendering and 1 for physx.

[lagunareturns]

selecting what cards for physx is irrelevant to sli, nvidia made it possible to use any nvidia card to handle it even two or more cards without sli, why because if you had old nvidia physx capable cards, it is obvious sli isnt possible but you can use them to handle physx and even two of them...

also you dont realise that obviously physx is thread based so when it is not in sli each card selected for physx handle each thread, or divide the threads between them... when you run sli the thread is processed equally between the two...

so here is my freaking answer you can use more than one card, i was able to select it, maybe they removed option but less than 6 months ago i was able to do it, and obviously i wasnt using sli nor I was able to since the graphic cards had a big age gap