Hitting the VRAM limit

[aduman]

No problem man, I am always up for helping nice people in the forum .

 

I know the design of the Corsair 550D it is a pretty good case and I like the overall built quality. You are geared up pretty good so far and that 2nd GTX 780 Ti will fit perfect in your built. But it is a matter of truth that more fans will not help you with the cooling of the first GPU. And since you have already a AIO watercooler in there I wouldn´t bother and stack more fans in there.

The best case scenario depends on 2 things IMHO. First you need to look at the overall air flow in your case. You want to make sure that you can maintain a positive air pressure in it. That gives you better cooling for all passive elements and helps you avoiding getting too much dust in your machine. With that being said a 550D has good airflow, and I do not see too many issues here.

Second thing is you should think about the possibilty of adding later down the road a watercooled loop. If you are sure that you won´t do thast you can go with what ever design of the boardpartners you want, but if you have been thinking about it I´d buy EVGA´s ACX design, this is perfect for aircooling and the PCB meets EK´s requirement for the standard full cover waterblock .

Then there´s another point, the first card needs to have a suction cooler design such as the reference design. If not the temps will go really high and I mean a lot higher that necessary. I tested this myself with the EVGA GTX 780 Ti ACX. When this card was in 1st slot I had in Unigine Valley around 83° Celsius. When I put the card in 2nd slot I ended up having 58° Celsius. I mean that´s a huge temp delta right there.

The best way for a 2 way SLI on aircooling for performance is 1st card in reference design (suction) and 2nd card in a design such as EVGA´s ACX (blower). Or for sure if you want it for the looks when you have a windowed side panel 2 ref cards .

 

Sorry I wrote again a lot.. another wall of text. But this might help you I think .

 

EDIT: As a personal remark from me... a GTX 780 Ti SLI is totally kick ASS . BTW haha I like your avatar Frank Drebin ftw .

He is a true legend, a genious without a doubt! And I can't even sleep at nights just because of the excitement for my new setup!

No problem man I actually really appreciate your long replies. Unfortunately I care about looks and I won't be able to stand the looks of two different coolers. Don't get me wrong please, I won't be able to game on that setup comfortably, it would bug me like hell!

My mobo is a Maximus V Formula man, it's going to be either two reference design coolers or two acx coolers. I need your input again. Thank you.

[Najuno]

He is a true legend, a genious without a doubt! And I can't even sleep at nights just because of the excitement for my new setup!

No problem man I actually really appreciate your long replies. Unfortunately I care about looks and I won't be able to stand the looks of two different coolers. Don't get me wrong please, I won't be able to game on that setup comfortably, it would bug me like hell!

My mobo is a Maximus V Formula man, it's going to be either two reference design coolers or two acx coolers. I need your input again. Thank you.

 

Hey no worries I get that point very well, because I´m the same way. And even if I couldn´t see the cards because of a closed case it would probably bother me . But in terms of performance on air it would make the most sense.

The Maximus V Formula is a nice RoG board and assuming since this is Z77 you are running either an i7 3770K or i5 3570K which is very good, then you won´t create any bottlenecks with the CPU.

My only concern is that I hope your PSU is sufficient for 2 GPUs. I personally would at least go with 750 Watts, but that´s really the lowest and better would be to have some reserves. I use a Corsair AX860 full modular PSU it is just perfect for a 2 way SLI setup. I do have plenty of space for overclocking (I overclock all my hardware as far as it goes). Then for sure I made some tests how much power my machine draws out of the wall and I was fairly surprised.

With 1 GTX 780Ti and 2 custom watercooled loops (including 2 pumps and lots of extra fans), including hard overclocks I ended up having under full load 449 Watts total. As you can imagine I was kinda surprised. nVidia says on the box of their card you need to have at least 600 Watts PSU (the reason for that is clear, this could get an issue with a non certified cheap PSU).

With 2 GTX 780 Ti and the very same setup as with 1 I ended up drawing 697 Watts total under full load out of the wall.

 

So you see the 750 is very realistic. But to go bigger in order to have it quieter is better (fan won´t spin that much).

 

Alright that was an excourse to the PSU island ... but if you ask me which design, I would buy the reference design. The nVidia stock cooler is really a solid cooler that even allows you mild overclocks. It isn´t too noisy, and you even get the green lighting on the cards . But with the ref design the whole setup will run a bit cooler and you don´t have to deal with a lot hot air in your case. And the foremost important part is the first card won´t get too hot. I would buy the EVGA GTX 780Ti in SC version (SC =SuperClocked means mild factory overclock).

[aduman]

Hey no worries I get that point very well, because I´m the same way. And even if I couldn´t see the cards because of a closed case it would probably bother me . But in terms of performance on air it would make the most sense.

The Maximus V Formula is a nice RoG board and assuming since this is Z77 you are running either an i7 3770K or i5 3570K which is very good, then you won´t create any bottlenecks with the CPU.

My only concern is that I hope your PSU is sufficient for 2 GPUs. I personally would at least go with 750 Watts, but that´s really the lowest and better would be to have some reserves. I use a Corsair AX860 full modular PSU it is just perfect for a 2 way SLI setup. I do have plenty of space for overclocking (I overclock all my hardware as far as it goes). Then for sure I made some tests how much power my machine draws out of the wall and I was fairly surprised.

With 1 GTX 780Ti and 2 custom watercooled loops (including 2 pumps and lots of extra fans), including hard overclocks I ended up having under full load 449 Watts total. As you can imagine I was kinda surprised. nVidia says on the box of their card you need to have at least 600 Watts PSU (the reason for that is clear, this could get an issue with a non certified cheap PSU).

With 2 GTX 780 Ti and the very same setup as with 1 I ended up drawing 697 Watts total under full load out of the wall.

 

So you see the 750 is very realistic. But to go bigger in order to have it quieter is better (fan won´t spin that much).

 

Alright that was an excourse to the PSU island ... but if you ask me which design, I would buy the reference design. The nVidia stock cooler is really a solid cooler that even allows you mild overclocks. It isn´t too noisy, and you even get the green lighting on the cards . But with the ref design the whole setup will run a bit cooler and you don´t have to deal with a lot hot air in your case. And the foremost important part is the first card won´t get too hot. I would buy the EVGA GTX 780Ti in SC version (SC =SuperClocked means mild factory overclock).

 

Thanks again man, we have the exact same PSU! I've bought it for future plans for SLI and it turned out to be a very good investment. Does the reference design has any drawbacks? You know, performance wise, overclocking capabilities etc. The looks on the ref. design is just amazing... Nvidia really did a great job on the design.

 

Oh btw, I'm running a i7 2600k overclocked at 4.5 Ghz on 1.360V.

[Faa]

Don't you guys want to understand that cached vram doesnt have an impact on your performance? I see my vram capping in many games at 1080p just because theyre caching what might be needed for the next frames doesn't mean more VRAM will give me more performance at all. Caching vram is just pointless especially with modern gpu's, monitoring vram means nothing although.

[maazster]

The 4GB of VRAM gives the 290X quite good performance at 4K because of its massive 512bit bus.

Don't forget the 64 ROPs

[Najuno]

Thanks again man, we have the exact same PSU! I've bought it for future plans for SLI and it turned out to be a very good investment. Does the reference design has any drawbacks? You know, performance wise, overclocking capabilities etc. The looks on the ref. design is just amazing... Nvidia really did a great job on the design.

 

Oh btw, I'm running a i7 2600k overclocked at 4.5 Ghz on 1.360V.

 

Well,

then you should be all set and ready to go .

 

Drawbacks with nVidia ref design? No not really, maybe the card won´t go the extra mile for overclocking really hard... but I would not want to do that on air anyways because most of these OCs don´t work on a stable basis (there are always exceptions). It won´t throttle at all with normal OC.

 

Yeah this CPU won´t bottleneck a thing at all .

[aduman]

Well,

then you should be all set and ready to go .

 

Drawbacks with nVidia ref design? No not really, maybe the card won´t go the extra mile for overclocking really hard... but I would not want to do that on air anyways because most of these OCs don´t work on a stable basis (there are always exceptions). It won´t throttle at all with normal OC.

 

Yeah this CPU won´t bottleneck a thing at all .

 

So reference design it is then?

[Najuno]

So reference design it is then?

That will be your own decision but if I´d have to do that I´d go for ref design (if you ever want to go with watercooling the ref brings another advantage with it because you do not have a custom PCB and getting a heatsink is easy).

[aduman]

That will be your own decision but if I´d have to do that I´d go for ref design (if you ever want to go with watercooling the ref brings another advantage with it because you do not have a custom PCB and getting a heatsink is easy).

With all the airflow talk I've never thought about the exhaust on my case. It only has the 140mm fan that comes with the H90 on the back. It doesn't push much air out. It's mounted between the radiator and the back of the case. Should I get two of the new SP140 fans. I need to have a good exhaust and good cooling for the radiator simultaneously. Perhaps I should start a thread on cooling section. Thanks man.