Will it fit in my mATX build (Corsair 350D)? Two GPUs (GTX 780 ti + 750 ti) and a single-slot card (InfiniTV PCI-e)

Eggz · Mar 28, 2014

Background

Currently, I have more installed on my LGA2011 motherboard than I can physically mount to it. It's a mATX build, and I am using a PCI-e 16x riser cable for my second video card, but I'd like to mount the card if possible. My only thought is to upgrade the motherboard, which would also benefit in other ways. But the question is whether it's worth it given that the new motherboard will still only have 4 slots (I'd have to hang a card over the bottom edge)?

Here are my relevant specs, since this is just a spacing issue:

3930k
GTX 780 ti (double-wide PCI-e card)
GTX 750 ti (double-wide PCI-e card)
Ceton InfiniTV-4 (single-wide PCI-e card)
All in a Corsair 350D

The problem (coming up short)

You'll notice my card take up 5 physical PCI-e slots, and LGA2011 mATX motherboards only have 4 PCI-e slots - one short!

My current motherboard's PCI-e layout, from the CPU socket away from the CPU socket, is 16x - 1x - 16x - 1x. Here is a picture:

I have my GTX 780 ti in the top slot (16x), nothing in the next slot (1x), and the InfiniTV-4 in the bottom slot (1x). Between the two cards, I have my GTX 750 ti connected via a riser cable, since it wouldn't fit otherwise.

Possible solution (Rampage IV Gene?)

This Asus motherboard's PCI-e layout, from the CPU socket away from the CPU socket, is 16x - 1x - 16x - 16x. Here is a picture:

In order to get this to work, I would have to put a video card in the top slot, which would cover the 1x slot. Then I've have to put my InfiniTV-4 in the third slot, which is a 16x slot even though it's a 1x card. Finally, I'd have to put the other video card in the bottom slot, letting the card hang over the edge of the motherboard.

A major concern (Is hanging over okay?)

If I hang the second graphics card over the edge of the motherboard on the bottom slot, what are the potential issues? I see it will cover up the OC button on the motherboard, as well as a few other things. But I may not need them all the time.

Another issue I see is that the hanging card might hit the power supply. It is below the motherboard in the 350D.

Is it worth it? (If this all fits, I think so.)

My current motherboard has limited OC abilities. That leaves my processor and RAM partially unused. Also, it has a few compatibility issues that a high-end motherboard wouldn't run into. So, if getting the Gene will also let me mount all my cards, I'll go for it. But without the mounting, I can't justify the cost.

Any planning thoughts would be appreciated.

faalin · Mar 28, 2014

what is the reason for the 750? If your using it for physics you really don't need it, the 780 ti or 3930k can handle that. Seems to be wasting space, causing unwanted heat, and using power that it doesn't really need to.

If your wanting to move to another motherboard then most likely you will need a new copy of the OS, only guessing your on windows 7 oem, and if so it will not transfer to the new motherboard.

Eggz · Mar 28, 2014

The 750 ti is for PhysX. It makes a substantial difference. Here are the results of PhysX benchmarks I've done on my system with and without the card, and with and without optimized drivers: https://drive.google.com/folderview?id=0B0DnoLWfOUZxbGdsSFk5NmFIVW8&usp=sharing
I play mostly PhysX games, and they have been very noticeably better with the card dedicated to PhysX, especially compared to using the CPU.

That the link I posted with benchmark results has two folders in it, and one is "With Driver Problems." If you want to see the results of a functioning dedicated PhysX setup, you needed to click the link and open the folder called "After Fixing Driver Issues." Here is a direct link to the correct folder: https://drive.google.com/folderview?id=0B0DnoLWfOUZxbHVBQnh5N3ZRS2c&usp=sharing

To make it even easier, here are the screen shots showing the results of the 780 ti alone, as well as the results of the 780 ti with the 750 ti dedicated to PhysX, with proper drivers.

GTX 780 ti only (main & PhysX): 79.3 average and 104.6 max fps

GTX 780 ti (main) + 750 ti (PhysX): 122.1 average and 218.5 max fps

I know it's "just a benchmark," as some like to say, but dedicated PhysX makes very big difference. Game performance has also been noticeably smoother since I properly configured the 750 ti as a dedicated PhysX card (in PhysX games).

If you'd like to read about it, here is an article showing that, the more powerful a main graphics configuration is, the more it benefits from dedicated PhysX.

http://alienbabeltech.com/main/using-maxwells-gtx-750-ti-dedicated-physx-card/

Also, I've already researched OS migration and called Microsoft about this. Mine is Windows 8.1 Pro. I will get an authentication error, and I just have to call to get it fixed over the phone. Already have a case number for if I decide to go this route.

. . . Anyway, it's already established that dedicated PhysX is a good thing. Let's get back on track here. I'm trying to fit some stuff in a case.

Hopefully, someone out there has experienced hanging over a card. Has it worked?

faalin · Mar 28, 2014

I noticed after I posted it that's why I deleted the post.

As long as there is slots in the back of the case to screw the card into the fan hanging down past the motherboard wont be a problem. you need to look and see how much room you have between the bottom of the MB and the top of the PSU, that might be your issue.

as for everything on the bottom of the board it should fit under the fans on the videocard. I run asus MB's and never have I used the start\reset or go button. The go button is a preset overclock button for the bios and should never be used, always do manual overclocks as the presets us to much voltage on them.

If you have to you can cut the mounting bracket on the videocard to a single slot if the case doesn't have enough mounting slots at the bottom. I have an old computer that I play around with running 4 gtx 8800 ultras and the last card I had to cut the dual mounting bracket down to a single slot for it to fit in the case.

most people don't like win 8 so I figured you were still on 7. Microsoft made it a little easier with 8 to transfer os's to another computer unlike win 7 oem that is stuck to the MB.

Eggz · Mar 28, 2014

Yeah, that's what I was thinking. It's too bad because I can't really tell without ordering the motherboard. Lamez!

As for your previous post. I didn't realize you deleted it. My bad. I've gone back and adjusted mine, though I may leave some of it for clarity in case others come across the same issue.

In terms of the spaces in the back of the case, I have 5 slots, so that's a sign that what I want to do is possible. At least it shows that I won't need to mod my case if the motherboard will allow mounting of both cards.

i7Baby · Mar 30, 2014

I think you need to get a bigger case! Then fit in a mobo with enough slots and spacing. What you've got feels more concocted than built. And I get the feeling you like to fiddle. I think you've run out of room to fiddle.

But thanks for letting me know the effect having a PhysX card can make. I didn't think it'd make anywhere near that sort of difference.

Eggz · Mar 31, 2014

@i7Baby

You caught me as a tinkerer

As for the case itself, the size is perfect. My constraint is just the motherboard, and I really don't want a large computer in the first place.

I can definitely live with the PhysX card the way it is, but it would just be a little more solid if it were screwed in to the proper mounts. Right now, it is secured parallel to the motherboard rather than perpendicular. Not really a problem, and it actually looks very nice through the case window.

I'll just see what happens. Perhaps I'll order the motherboard through Amazon, since they allow free returns. That way I won't risk as much by trying it out.

Finally, as for the dedicated PhysX card, it's really amazing! At least, when it kicks in. The actual graphical load of PhysX isn't intensive compared to a 3D environment, but I noticed something after playing around for the last couple weeks. Looking into it, video cards first came about because of a division of labor. CPUs are good at multitasking, but they don't do single-paralleled tasks very efficiently. Conversely, GPU are great at paralleled tasks but pretty bad at multitasking.

With that in mind, it makes more sense that a non-demanding task like PhysX calculations slow down even a powerful graphics card. The main card's task of rendering and maintaining a 3D world takes up a good chunk of its processing power, and then all of a sudden, an explosion pops up our of no-where, requiring rendition of a moderately-intensive graphic. Then it goes away and comes back, each time different than before. That is the essence of multitasking, and it's happening on a graphics card. But graphics cards are very bad at multitasking. Adding a dedicated PhysX card prevents PhysX from interrupting the main card's singular job of rendering the 3D world, and the PhysX card singular job is PhysX. Then all graphics cards run without multitasking. That's my theory based on reading and experimenting, at least.

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Will it fit in my mATX build (Corsair 350D)? Two GPUs (GTX 780 ti + 750 ti) and a single-slot card (InfiniTV PCI-e)

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