# [SOLVED] Multi-gpu mode questions



## BluTurtle (Sep 1, 2008)

Hello all,

I've decided to haul in my gaming rig and plan to build a new one from the ground up with top market (ATM) hardware. I've gone over all the new hardware and am ready to buy everything when I tie up loose ends with money. I have a few questions with the graphics cards, to be sure so I dont make an unnecessary or unoptimal purchase.

I plan to buy two XFX Geforce GTX 295 Graphics cards in quad-sli to power my new rig (not physically obviously). I have two XFX Geforce 9800 gt's running sli currently and saw a few things on the internet about multi-gpu mode with nvidia cards which slaps one card with graphics processing, and one with physx. now this is my question, sorry if the stuff above is not a good use of your time:

Am I able to run two gtx 295's in quad-sli to handle graphics with one 9800 gt to process physx? is it restricted to simply one card to power graphics and one to physx? if I can run two cards on the graphics end, is it easy to setup multi-gpu like sli is on the nvidia control panel? sorry if this is a simple question(s), I am not saavy in multi-gpu mode, but just straight-up sli between two identical cards. even if all this power may not even be necessary, I'm aiming for (again, atm) top shelf gaming, and whatever gaming will throw at my rig down the road.

There is also this issue with multi-gpu is that I need two monitors, or dual display input to run seperate graphics and physx processing properly. I'd prefer using dual display input, but nor my current monitor or the one I'm going to buy has both a dvi AND vga port. is there a specific adapter or a daisy-chain display cable (not likely) with both dvi and vga outlets to therefore go in the graphics, and then physx cards while all on one monitor?

the next series of questions is aimed at cooling. My 9800's currently have no additional cooling (stock fans), but more or less ventilation, so it's a little warm in my system. Is there specific cooling I can use that accomodates gpu cooling, that supports a gtx 295/9800 gt? if so, which is best? I'm pretty sure I will definitely need something if I'm to run two gtx 295's AND a 9800gt (if possible) properly.

I've researched around, but I've just gotten confused with all the information, and as to which is best or not. I'd appreciate a straight-up answer as to how I can setup a Multi-gpu system with the right monitor hooked up, and proper cooling for it. Perhaps if just using two gtx 295's in sli, will get the job done, I'd appreciate an answer before I break my system over it.

Thanks in advance.


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

SLI and PhysX are two different things. You can SLI two cards and then have another doing PhysX, if you can find a motherboard with the necessary slots. However, having a separate card to do PhysX is really just a gimmick and with two GTX295s (or even a single one, frankly) you'll see essentially no difference in performance, maybe an additional 5fps at most. SLI itself is a gimmick in many ways. Even on a 2560x1680 screen a single GTX295 will handle any game at its maximum settings at a decent resolution. 

By the way, two GTX295s and a 9800GT (and presumably a Core i7 965/975, correct?) would require a 1200W or greater power supply, and the only one I think I could recommend would be this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703020&Tpk=PC Power and Cooling 1200
Which costs about as much as a single GTX295 on its own. You'll also need a high-end full tower case if you want to keep these cards cool. You might even want to consider water cooling.


Seriously, I would suggest saving some money and sticking with just a single GTX295. That way you can save a ton on the motherboard (and you won't need to use one of the buggy Nvidia boards), power supply, and case (I'd still recommend a full tower or very good mid tower, but you won't need to think about water cooling unless you really want to). And you'll still have some of the best performance out there.

If you do use two GTX295s and a 9800GT, at least run [email protected] in your spare time, ok? http://en.wikipedia.org/wiki/[email protected] :wink:


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## Tyree (May 10, 2009)

*Re: Multi-gpu mode questions*

Very solid advice! Nothing to be gained other than bragging rights.
The price of running more than one graphics card just does not justify the price for such a minimal gain in performance.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

Thanks very much for responding so quickly, lol.

I do have a 1200w psu, and a new full tower is in mind so I'll be sure to look for a well-ventilated one. A i7 is also on the list. the mobo I had in mind is the evga x58 sli classified, which does allow for things such as two graphic processors and one physx and different combinations and such.

Hmm, good thing I asked about physx before acting on it, so thanks for that. I may stick with one gtx 295, and maybe a second one, but I'm considering that heavy now. if I did, i'd do quad-sli, but dual (in one card) is still good enough for now I suppose. games I was looking at for upgrades would be crysis 2, left 4 dead 2, and Batman: Arkham Asylum and etc. Not that I cant run these games with my current rig, but I figured from the release of newer hardware/technology and such, it was about time for an upgrade. 

as for cooling, would you suggest I simply find bigger/more powerful fans? When I buy the gtx295, I want to make sure it stays cool and live long and all that.

Thanks again.


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

What brand is the 1200W? If it's from a shoddy brand you may need to get a new one anyway.

I wouldn't suggest the EVGA Classified. EVGA isn't known for making great motherboards, and the Classified has several design flaws such as painted heatsinks so the board's northbridge will run very hot. It sacrifices functionality for looks. If you want an i7 build I would recommend the Asus P6T series (NOT the P6T6). I don't know if you'd still be able to use SLI, however. If you really wanted to go quad-GPU you could use the P6T and two Radeon 4870x2s in Crossfire, though again the performance increase isn't really worth the cost.

I would recommend better cooling for the GTX295, except they don't make custom coolers for it, and most of the general ones either aren't any better than the 295's stock, or don't support dual GPU cards. So you're stuck with either stock or watercooling.

If you really want the latest and greatest, wait until spring of next year, we've got Core i5 coming out (better bang for buck than i7) and probably the first wave of DX11 cards (GeForce 300 and Radeon 5000).


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

Hmm, very interesting.

the brand of my psu is Ultra, but it's been pretty faithful for the 2 years i've had this rig. with the mobo, I just looked at the Asus P6T. it allows for sli and the reviews look pretty good, with a better price as well. so would you then reccomend I jump into that instead of the evga mobo? as for case cooling, I looked at a bunch of fans and picked out ones with good reviews, and plan to install 'em when I get the case. as for the graphics card, theres a fan that connect into a pci slot, so I figure that would help ventilation, right?


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

Eeeeehh... Ultra definitely isn't known for quality. It may have done well for your current system because it only really needs an 800-900W to sing--the extra wattage means you weren't pushing the Ultra 1200W too hard so it hasn't been too stressed. With two GTX295s, though, I'd be worried. It might be worth investing in a Corsair HX1000W.

The P6T is definitely a better choice in most all respects than the EVGA.

Most full tower cases should already have very good airflow, no need for extra fans. You already have your case though, right? Could I have a link? For aftermarket case fans, both Antec and Scythe are very good, and Apevia is decent (the only thing Apevia is good at making is fans, by the way, and there are better choices even then).

The PCI coolers aren't a huge help. They may drop temps a couple of degrees celsius, or they may not lower temps at all. It depends on the specific one, case design, the graphics card, and pure, random luck.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

hmm, I guess I could look into the Corsair psu, it should still do decent for the system i'm looking at right? with a gtx 295 (maybe 2), the asus mobo, dvd-drive with dual-layer function, 1.5tb hdd, and an i7 with its heatsink.

The case i'm using is an Ultra M923: http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=3319620&CatId=1510

It's pretty decent I suppose, but I figure there are better full towers with better ventilation and such. with the extra case fans, it would be better to have a better one than standard stock fans that come with the case, no? i'll look at the antec/scythe when I get a chance. finally with the pci cooler, surely it would do something? would it do any help than it not being there? the one in question is located here:
http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=120565&CatId=494

also, this struck me when I looked at the asus, and was just wondering, to ease my mind on it. are there specific drivers for the p6t? could I use nforce at all like my 780i board to keep the system nvidia green?


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

The Corsair HX1000W should do for that system with two GTX295s. If you've changed your mind and are going to go with one GTX295 (gah, I'm getting tired of typing that :grin: ) then the HX850W should do admirably (by the way, the HX850W has the highest rated efficiency of any power supply that hardwaresecrets.com has tested and is one of the ones I recommend most highly... in fact, it may even be good for two GTX295s since it can deliver up to 1000W before shutting off).

That case doesn't have great ventillation, looks like just two 120mm exhaust fans. Even with more powerful fans from Antec or Scythe you may still run hot. If you're willing to spend the money, the Antec 1200 or CoolerMaster HAF cases offer very good airflow, and have lots of room. I own an Antec 900 (mid tower version of Antec 1200, the design is mostly the same) and they are very nice cases.

That slot cooler looks better than most of the ones out there, two fans should offer better airflow than just one of course, and the solid plastic frame is better (and quieter) than the hollow shell most use. It doesn't intake/exhaust air like most other slot coolers do, but it should definitely help draw cool air up from the bottom of your case toward the GPU. Normally I don't recommend slot coolers, but this looks like a good one.

I'm sorry, I don't understand your last question? Are you asking if you can run Nvidia nForce motherboard drivers on an Asus Intel x58 motherboard? If so, no. Drivers are hardware specific.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

Hmm, typing gtx295 alot huh, lol. well if I decide on two or one gtx295s (lol) i'll pick the corresponding psu for it, thanks.

As for the case, I'll be sure to look at the those you suggested, with the fans too. and I suppose then I'll grab the pci cooler if it will do something.

Yes, that was my last question rephrased lol. hmm, so that I cant, will I still be able to use my Graphics cards normally as if it was a nvidia board. I mean like it says it can do sli, but will it be any different really from a nvidia board. will I still be able to access the nvidia control panel? (probably) I dont suppose it will act any differently than any other mobo, but you know, just to be sure.


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

Yes, it should still work just the same. I think the only advantage the SLI boards offer is that you don't need an SLI bridge, but since those usually come with the cards that's not a huge benefit. The cards will still work fine, and the Nvidia control panel is included with the display drivers.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

Oh interesting. So you're saying with this p6t board and the graphics cards, I dont need that tid-bit bridge to use sli? hmm, as for these asus drivers then, would it be somewhat as easy as nvidia, or am I going to have to traverse a forum to find the latest updates for them?


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

No no, I mean that with an SLI motherboard I didn't think you needed the bridge. Turns out I'm wrong and you still need it. I honestly don't see any point in getting an SLI motherboard now, especially since they're such a pain to set up and/or overclock (two times out of three). But you'll still need the bridge, either way.

Asus has very good driver support, you can download them from their website:
http://www.asus.com/
They're one of the leading motherboard manufacturers, alongside Gigabyte, you should have nothing to worry about with the P6T.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

hmm, thats good. I never really had much trouble setting up a sli system, just an extra card in the adjacent slot, then stick the bridge and bam. so its not much change then as to how i'll build it up then. alright, thats good that asus also has good support.

alright, well i'm pretty confident about this now, so just as a last question (or maybe a last set, lol), will this hardware, such as the mobo and graphics cards and pretty much all the devices, work well with windows 7 64bit? I plan on getting that with the new rig, but I wonder if compatibility issues will arise or not.


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## Phædrus241 (Mar 28, 2009)

*Re: Multi-gpu mode questions*

You shouldn't have any issues running Windows 7 at all.


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## BluTurtle (Sep 1, 2008)

*Re: Multi-gpu mode questions*

Alright, well I guess i'm set then.

Thank you very much for your help, and i'll be sure to remember who helped me select the right tech for my new rig when i'm gaming. I'll also check out that [email protected] thing you mentioned earlier regardless of the final setup.

Peace out. <(^__^<)


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