SLI Question

[Heisennburgg]

Hey all, I have a question about SLI compatibility that I was hoping I could get some confirmation on. About a year ago, I built my first PC and went with an EVGA GTX 780 SC edition to start out with since it fit the budget the best at that time. Well about a month ago, I had a friend of mine sell me his GTX 780 FTW edition for $50, which is literally impossible to turn down, so of course I bought it. It's also an EVGA branded card, the only difference is that it's the FTW edition and my other card is a SC edition...so my question is would I still be able to run them in SLI? The SC edition has a default clock speed of 967MHz and the FTW edition has 980MHz if that means anything. I'd really appreciate an answer, so thanks in advance to anyone that answers!

[Uwillparish]

yes, The clock speeds would just turn down to the lowest in the chain

 

EDIT: welcome to the forum!

[hypnodog]

It will work just fine as it's the same GPU. The FTW may slow down to the SC speeds, though.

[blueballs]

Yes and welcome to the forum.

[Uwillparish]

It will work just fine as it's the same GPU. The FTW may slow down to the SC speeds, though.

Ninja'd 

[Pizzatime6]

Hey all, I have a question about SLI compatibility that I was hoping I could get some confirmation on. About a year ago, I built my first PC and went with an EVGA GTX 780 SC edition to start out with since it fit the budget the best at that time. Well about a month ago, I had a friend of mine sell me his GTX 780 FTW edition for $50, which is literally impossible to turn down, so of course I bought it. It's also an EVGA branded card, the only difference is that it's the FTW edition and my other card is a SC edition...so my question is would I still be able to run them in SLI? The SC edition has a default clock speed of 967MHz and the FTW edition has 980MHz if that means anything. I'd really appreciate an answer, so thanks in advance to anyone that answers!

I believe everything must be the same to sli cards or at the very least it will downclock one of the cards to work. Also check the device ID's of the gpu's. If it has a different device ID it wont work in sli period. Had that issue when I had two 780 sc acx 6gb cards.

 

To check the Device ID number go to nvidia control panel then click on system information. From there scroll down in the menu that pops up till you see device ID.

[SirWendall]

As long as they are both 780s

[hypnodog]

Ninja'd 

Haha, You posted that as I was typing. If only I could type faster than 40 WPM...  

[Pizzatime6]

As long as they are both 780s

And have the same device ID.

[SirWendall]

And have the same device ID.

Oh yeah 

[Pizzatime6]

Oh yeah 

I was so pissed when I had to RMA my newer 780 becuase of this. Also a good reason to ask this before buying a used card for sli.

[xToFxREAPER]

Itll work fine, gpu boost will lower the clocks of the FTW but because they are the same chip they will run perfectly fine. Its no different then when i tested my friends gtx 780 msi gaming edition with my own lightning edition 780 prior to buying the second 780, The faster card gets slowed down a bit to the clock speeds of the second card and in many cases once gpu boost activates in game they boost together.

[Pizzatime6]

Itll work fine, gpu boost will lower the clocks of the FTW but because they are the same chip they will run perfectly fine. Its no different then when i tested my friends gtx 780 msi gaming edition with my own lightning edition 780 prior to buying the second 780, The faster card gets slowed down a bit to the clock speeds of the second card and in many cases once gpu boost activates in game they boost together.

I wonder....Couldnt you overclock the second card to match the faster one instead? Not that 20mhz is a huge deal just wondering. Never got a chance to try it myself.

[Heisennburgg]

Thanks for all the replies - I just hooked it up and enabled SLI and everything is working fine, I ran a few benchmarks and I'm getting great performance. Played The Witcher 3 in SLI for about 15 minutes as well and was averaging 50FPS with everything on ultra. Only problem is the temperatures, even though I have the fan speed turned to 100% when I'm gaming on both cards.

[Uwillparish]

Thanks for all the replies - I just hooked it up and enabled SLI and everything is working fine, I ran a few benchmarks and I'm getting great performance. Played The Witcher 3 in SLI for about 15 minutes as well and was averaging 50FPS with everything on ultra. Only problem is the temperatures, even though I have the fan speed turned to 100% when I'm gaming on both cards.

What are temps like?

[GrimNeo]

Hey all, I have a question about SLI compatibility that I was hoping I could get some confirmation on. About a year ago, I built my first PC and went with an EVGA GTX 780 SC edition to start out with since it fit the budget the best at that time. Well about a month ago, I had a friend of mine sell me his GTX 780 FTW edition for $50, which is literally impossible to turn down, so of course I bought it. It's also an EVGA branded card, the only difference is that it's the FTW edition and my other card is a SC edition...so my question is would I still be able to run them in SLI? The SC edition has a default clock speed of 967MHz and the FTW edition has 980MHz if that means anything. I'd really appreciate an answer, so thanks in advance to anyone that answers!

Yes, they will run in SLI but the FTW card will downscale in MHz to match the slower card. You can always overclock the sc card to match the speeds.

 

Source.

I have a Titan X reference and Titan X SC in SLI.

 

 

Welcome to the forums.

[xToFxREAPER]

I wonder....Couldnt you overclock the second card to match the faster one instead? Not that 20mhz is a huge deal just wondering. Never got a chance to try it myself.

Yeah, in msi afterburner (or whatever you opt to use) you have to de sync the cards. By default whatever the program is makes a point of trying to sync the boosts, fans etc which is why oc settings typically effect both cards. when de synced you can oc your boost, memory and control fans and voltage seperately for both cards.

[Br3tt96]

I wonder....Couldnt you overclock the second card to match the faster one instead? Not that 20mhz is a huge deal just wondering. Never got a chance to try it myself.

That would be best. Overclocking the slower one plus 20mhz would be perfect. Any card can do +20mhz.

[Heisennburgg]

What are temps like?

When I'm playing The Witcher 3 the main card gets up to 75-80C Second card when gets to about 60-65C if I'm in SLI. Anything I could do to solve this? I have 5 case fans set up perfectly for my case for the best air flow, and I even turn the fan speed on both cards to 100% when I'm gaming just to help them cool down better. I know the temps could be worse, but I see alot of people that do benchmarks are getting like 50-65C on average when gaming, so mine seem pretty high. I know it's not hot enough to damage anything, because apparently the 780 is able to safely run until about 90C from what I've heard.

[Pizzatime6]

When I'm playing The Witcher 3 the main card gets up to 75-80C Second card when gets to about 60-65C if I'm in SLI. Anything I could do to solve this? I have 5 case fans set up perfectly for my case for the best air flow, and I even turn the fan speed on both cards to 100% when I'm gaming just to help them cool down better. I know the temps could be worse, but I see alot of people that do benchmarks are getting like 50-65C on average when gaming, so mine seem pretty high. I know it's not hot enough to damage anything, because apparently the 780 is able to safely run until about 90C from what I've heard.

 

Honestly the top card is always going to run hotter then the bottom one. However this might also be because the game isnt using the second gpu at full load compared to the other one. Basically one card might be at 100% and the other running at 60%. Is there any way you can find out what the gpu useage is for the cards in game? If you don't know any software for this msi afterburner is a great tool to find this out.

[Uwillparish]

When I'm playing The Witcher 3 the main card gets up to 75-80C Second card when gets to about 60-65C if I'm in SLI. Anything I could do to solve this? I have 5 case fans set up perfectly for my case for the best air flow, and I even turn the fan speed on both cards to 100% when I'm gaming just to help them cool down better. I know the temps could be worse, but I see alot of people that do benchmarks are getting like 50-65C on average when gaming, so mine seem pretty high. I know it's not hot enough to damage anything, because apparently the 780 is able to safely run until about 90C from what I've heard.

I have a 780 ti in my mini-pc with its reference cooler running at 80C, And its fine as you said, The airflow between the cards is a bit starved, the only thing i can suggest to lower temps is getting a couple kraken g10's and 2 h55's and water cool the 2

[GrimNeo]

When I'm playing The Witcher 3 the main card gets up to 75-80C Second card when gets to about 60-65C if I'm in SLI. Anything I could do to solve this? I have 5 case fans set up perfectly for my case for the best air flow, and I even turn the fan speed on both cards to 100% when I'm gaming just to help them cool down better. I know the temps could be worse, but I see alot of people that do benchmarks are getting like 50-65C on average when gaming, so mine seem pretty high. I know it's not hot enough to damage anything, because apparently the 780 is able to safely run until about 90C from what I've heard.

What MHz does the top card run at when you are playing the game? What does the second card run at?

[Heisennburgg]

Honestly the top card is always going to run hotter then the bottom one. However this might also be because the game isnt using the second gpu at full load compared to the other one. Basically one card might be at 100% and the other running at 60%. Is there any way you can find out what the gpu useage is for the cards in game? If you don't know any software for this msi afterburner is a great tool to find this out.

 yeah I use Afterburner, it's a god send I'd be lost without it. Lately I've been monitoring my GPU usage and temps while playing witcher 3 cuz of how hard it makes both of my cards run, the second card never gets up to full load, the top card gets to about 90% full load while playing and about 75-80C while the second card gets around 60-65C. Both cards are not overclocked while I'm doing this, I put them both at default while testing them out. I'm currently overclocking both cards though and don't really see too much of a temperature difference when overclocking them like when overclocking my CPU.

[Heisennburgg]

I have a 780 ti in my mini-pc with its reference cooler running at 80C, And its fine as you said, The airflow between the cards is a bit starved, the only thing i can suggest to lower temps is getting a couple kraken g10's and 2 h55's and water cool the 2

I have NO experience with water cooling, but I'm willing to look into it some more. I've always wanted to give it a try anyway, it seems really fun. Only thing is being worried about leaking just like anyone else would be. How much do those cost a piece? In US dollars if possible.

[Uwillparish]

I have NO experience with water cooling, but I'm willing to look into it some more. I've always wanted to give it a try anyway, it seems really fun. Only thing is being worried about leaking just like anyone else would be. How much do those cost a piece? In US dollars if possible.

Well, The thing i was talking about is using a water cooling braket with a All in one cooler, That has less chance of leaking, less hassle, and less money, and will cost you somewhere near $200

 

Parts list:

2 h55's $120

2 Corsair n780 brakets $80

 

A open loop water cooler will cost you somewhere near $350 but will need space in your case, but it will also have a CPU block, so all of your components are in one loop