2-Card SLI Question

If I am interested in running two video cards (wouldn't mind going to three eventually, but the current one is so thick it hits the middle PCI slot!). Do I need to get the same exact video card for dual cards? Was thinking about getting a better, top of the line card than the one I have now. My current card is listed in my sig and rig info. Also, what would be the best way to ensure my PSU is large enough for another video card?

bumpage

if your going to go sli theres no point in getting a faster card , you will have to slow it down in order to run it in sli with the other one

technically you dont need to have the same make and model of card its just better if you do , less likelyhood of any issues , sli can be enough of a pain as it is sometimes without having to deal with any incompatibilities between card manufacturers

Tell me the make and model of your psu and ill tell you if it'll cope with sli on you system

I think a 600w PSU will be pushing it with dual 260s.

You do need the same card for SLI, so like you won't be able to get a 275 or 285 to SLI with your 260, you need to get another 260, but like what Archie said it doesn't have to be the exact same one, so you could get like an XFX 260 for example. The only thing that will happen then is that both cards will run at the same speed as the slowest one i.e. the faster card will downlock itself automatically to run at the same clock speeds as the other one.

VRAM isn't as much of a concern now as all 260s come with the same amount of RAM, but for the record, you'd need both cards to have the same amount of RAM, or card with the more RAM would limit itself to the same amount of RAM as the 2nd card as well.

There's nothing you can do about the size of graphic cards either, so when you get your 3rd one, it's going to be extremely cramped on that motherboard with some insane heat being pumped out.

Have you thought about leaving the GTX260 (great card btw ) and just running something smaller (that doesn't require as much amps) to handle your PhysX. I say this because not many games handle SLI and those who do, do not handle it well so, I see it as a hassle or waste of money.

My way, on the other hand, works very well for the most part, although, I can't honestly say it would perform better than SLI in a benchmark test but, seat of the pants... Yes!

Astalavista, can you suggest a card as an example of what you mean please?

Great information Everlong18. I doubt very very much that I'm going to go for three. The first 260 is doing a nice job as it is. No problems here. It handles the games very well. I just wanna go two card sli simply because I can really. :D But that's all.

Archie123, the PSU I have is Newegg.com - OCZ GameXStream OCZ600GXSSLI 600W ATX12V SLI Certified CrossFire Ready Active PFC Power Supply - Power Supplies

thanks for the info so far you guys. I'll give ya guys some rep points for all the help so far. Thanks! :D

OCZ make good PSU's (i have one so they must be good ) BUT although it is SLI compatible (meaning it has a few pcie power connectors) i would have to say you may run into trouble with it in sli.

That said it is borderline it MIGHT be ok , so if you do go sli/crossfire instead of buying a psu aswell give yours a go and see how it shapes up , you'll soon know if you have power issues (severe fps dips ingame , constant driver errors , your GPU's drivers may also flag up power issues via windows , aswell as loads of other supposedly unrelated errors) Riva Tuner is another fantastic app for keeping an eye on your GPU voltage supply , monitor it ingame watch out for any dips

good luck

Gudziel, I can only tell you what I had at some point, other than that, I would say that any of the Nvidia GS or GT cards will do a good PhysX job

I had an ECS 8800GT 512 card along with the GTX260. My problem was that my PSU was not handleing both cards correctly and once I got a bigger PSU, I sold the card but, all the small tests I did said that my average FPSs were better with both cards on.

Perhaps you may want to find one that does not require the newer plugs for power as those cards run a bit hot and are very power hungry... I think that the 85, 86, 95 or 96 series don't need that plug.

Again, research this as I don't have much clue. Perhaps I am wrong but I have yet to see any real changes in SLI or single card FPS and if so... minimal.

Just because you have the means does not mean is a solid investment... sometimes more is less

Everlong18 said:

I think a 600w PSU will be pushing it with dual 260s.

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According to this calculator - eXtreme Power Supply Calculator Lite v2.5, plugging in his system specs and going SLI with two 260's and running his system at 90%, he only requires a 406w PS, thus his 600w is plenty.

When using the calculator, make sure you choose "Single" CPU, since either a quad or dual core is "physically" a single CPU.

I've found that calculator pretty inaccurate. I used it when I first got my two 8800s in SLI and it said I needed about 430w, so I tried it with my 500w PSU, even though on the gfx card boxes it recommended 700w for SLI (500w for single card), and all that happened everytime I started playing a game the computer would just shut down. :huh:

So to be on the safe side for SLI 260's, personally I'd go for a 700w.

Any tool can be inaccurate if not fully understood and use correctly. Not saying you didn't but....

Also, If he has a good quality 600w power supply, he could run those two cards just fine, especially if he's not pumping power to an excess of other items - waterpumps, a host of fans, 3-4 hard drives, multiple CD/DVD drives, or heavy overclocking.

Just my two cents

we need to read all the posts we seem to be repeating each other

I thought the video cards were measured with Amps more than Wattage? I had 1 GTX260 + 1 8800GT and my 600W Thermaltake ToughPower (top of the line PSU from Tt) was not capable of handling it or was just barely able to push them because of the low amperage on the 12v rail.

Opinions vary on power supplies when it comes to pure wattage, but there's more to it than that. In addition, you also have to consider you electricity bill when running these things.

Personally I think the average gaming system probably doesn't require more than an efficient 650watt PS.

This...
Intel Core i7 965
ASUS P6T Deluxe
6gig Corsair TR3X6G1600C8D Dominator RAM
Creative X-Fi Titanium Fatal1ty Pro Soundcard
A pair of ATI 4870x2 in Crossfire mode or a pair of Nvidia GTX 295's in SLI mode

Is NOT a "typical" gaming system, and these are the systems that benefit from something more than 650watts

Reading reviews and gaining an understanding on how PS work has made me rethink the wattage wars and reinforces my total agreement about purchasing a quality power supply.

This is the conclusion on a review of my Antec "550" watt - Antec NeoPower 550 Power Supply Review | Hardware Secrets. Note that this "550" watt is capable of producing 650watts!

And ATI has certified this power supply for crossfiring two 4850's - ATI Radeon™ HD 4890 - System Requirements.

Here's a good article about selecting a power supply - TweakGuides.com - Hardware Confusion 2009. Scroll down to “Power Supply”

It's not always about wattage, it's also build, design, and efficiency. How to Buy a Power Supply: 7 steps - wikiHow

And lastly here's the recommended power supply wattage for two 4890's in crossfire mode -

• 500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireX™ technology in dual mode)
• Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSU for a list of Certified products

ATI Radeon™ HD 4890 - System Requirements

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AstaLaVista said:

I thought the video cards were measured with Amps more than Wattage?

Click to expand...

Yes, and it has to do with the total amps the +12v rail system is capable of delivering. If a power supply isn’t designed well, it will shut off with a high amperage demand. That's why some people talk about balancing a load across multiple rails - See here: Antec NeoPower 550 Power Supply Review | Hardware Secrets, the paragraphs after fig 20.

At any rate that's my two cents for the way I see things.