SLI GTX 770 4GB vs CFX R9 280X 3GB vs GTX 780 Ti 3GB

[wevsspot]

At the dismay of many around here..................

 

If I were spending my own money it would be the two GTX 770 4Gb cards.  SLi has worked great for me my last three upgrades (GTX 460s, GTX 570s and GTX 670s).  I'm sure there are plenty of good and valid reasons to go with the GTX 780, so I'm not trying to start a huge debate.  Just commenting on how I'd spend my own money.

[ccokeman]

Personally, I wouldn't go for the stock squirrel cage fan regardless of the price (especially if considering two in SLi).

 

You would be surprised how efficient they are in SLI. 

 

At the dismay of many around here..................

 

If I were spending my own money it would be the two GTX 770 4Gb cards.  SLi has worked great for me my last three upgrades (GTX 460s, GTX 570s and GTX 670s).  I'm sure there are plenty of good and valid reasons to go with the GTX 780, so I'm not trying to start a huge debate.  Just commenting on how I'd spend my own money.

 

I have no problem with going SLI  but if the choice is 2x 770's or 2x 780's I would take the 780's all day long.  

[NikoDG]

SLI GTX 780's is a tad out of my price range though at $1100. It's either SLI GTX 770's at $800 or a single GTX 780 Ti at $760 (possibly SLI in half a year or so).

[wevsspot]

Maybe I'm just scarred from previous experiences with squirrel cage fans.  Yes, they were effective in SLi but they were also very noisy.  So either they have done a great job reducing the noise, or most everyone isn't as sensitive as me to the racket a PC makes.  I water cool and keep case fans to a minimum as I like my rig as silent as possible.

 

I guess for Niko it may come down to instant gratification / performance right now, versus buying a single awesome card right now and possibly putting another in SLi down the road if needed.

 

If I were answering to some specific reasons I would go with the GTX 770 4Gb SLi it would be;

 

1. Extra 1Gb of VRAM (whether you'll ever need 4Gb of VRAM might be up for debate - but to have if ever needed)

2. I'm not a very patient person - when I make my mind up to buy something I just buy it

3. SLi GTX 770 4Gb will offer instant performance better than single GTX 780Ti in most game titles that support SLi profiles and looks to be a perfect fit for 2560x1440 resolution

4. SLi is cool just because we can  

[NikoDG]

I've actually had some people tell me that the 4GB versions don't actually add that much of a performance increase as they are still limited by the memory bandwidth. The GTX 770 has a 256-bit bus with 7000MHz GDDR5, while the GTX 780 has a much stronger 384-bit bus with 7000MHz GDDR5 (50% more bandwidth). I guess vram without bandwidth isn't of much use?

Edited February 6, 2014 by NikoDG

[wevsspot]

The 4Gb versions aren't severely limited by memory bandwidth, but more so limited by the performance of the GPU and the amount of VRAM any given application can make use of.  That is the the only reason that putting two GTX 770s in SLi with a total of 4Gb of available VRAM makes any sense.

 

I wouldn't even consider one of the 4Gb cards unless I intended to run SLi.

 

We haven't even started talking about the performance comparisons when you start overclocking the 770 GPU a bit.

 

I'm not a video card engineer, but I have a hard time believing that nVidia would pour money into developing a 4Gb GTX 770 if the memory bus was going to be a critical constraint.  

 

I don't know how to make it any clearer, if you don't need or don't think you'll ever need 4Gb of VRAM then it doesn't make sense.  Without SLi in the equation, there just isn't enough performance difference between the 2Gb and the 4Gb versions of the GTX to warrant spending the extra money on the 4Gb card.

 

I think you're at the point where you are looking for someone to convince you that the GTX 780 Ti isn't the best option.  And that's going to be impossible to do, because it's your money and hopefully you'll pick whatever option suits you best.

 

On the negative side of SLi;

 

1. Additional power supply requirements

2. Usually generates more noise

3. Top card usually runs hotter than bottom card

4. Can dump a ton of extra heat in your case

5. Some games (although none that I play) work or scale well with SLi

6. Some folks are sensitive to microstutter and that can be an issue with dual gpu setups

[NikoDG]

When you have two cards in SLI/CFX the vram is duplicated across both cards correct? Do the cards then unload half of the memory through their bus each? Say the first card unloads the first half through it's bus, the second unloads the second half, effectively doubling it's bandwidth? If that's how it works I can see how two GTX 770 4GB's in SLI would be a good choice. Although if they both try to unload the full memory I don't see how the 4GB version would outperform the 2GB version as they'd both be limited by bandwidth.

 

Sorry if I'm getting to be troublesome. I just want to be extra sure in my purchase before I make it

[Bosco]

The GTX 770 is a fairly quiet card, even my 780's I can't even hear them at all.

 

Being that you are only running one monitor if you have the gear I would go with the two 770's. However, if you think you will have more funds in the next few months, I would go with the 780TI, and grab a second one in a couple of months.

[wevsspot]

When you have two cards in SLI/CFX the vram is duplicated across both cards correct? Do the cards then unload half of the memory through their bus each? Say the first card unloads the first half through it's bus, the second unloads the second half, effectively doubling it's bandwidth? If that's how it works I can see how two GTX 770 4GB's in SLI would be a good choice. Although if they both try to unload the full memory I don't see how the 4GB version would outperform the 2GB version as they'd both be limited by bandwidth.

 

Sorry if I'm getting to be troublesome. I just want to be extra sure in my purchase before I make it

 

NP Niko - it's a lot of money to invest and we can all understand your desire to make the best decision possible.  To be clear - running SLi does not "double" the available VRAM.  The total amount of usable VRAM is equal to the amount of VRAM on a single card.  So if you have two 2Gb cards, you have 2Gb of usable VRAM.  If you have two 3Gb cards, you have 3Gb of usable VRAM and so on.  Think of VRAM on an SLi setup as memory data that is mirrored between the two GPUs.

 

Each GPU needs to be able to address the memory banks that are physically on that card.  The GPU on card one can't communicate with the memory banks on card two.  There are a couple different rendering options when using SLi.  AFR (alternate frame rendering) or SFR (split frame rendering).  For once in the computer world those descriptions are actually pretty accurate.  Using AFR each gpu is responsible for rendering a separate frame (functioning much like a RAID0 setup on two hard drives).  Using SFR each GPU is responsible for rendering 1/2 of frame displayed on your monitor.  In either case the individual GPU must use the available VRAM that it is physically connected to on that card. You essentially have duplicate memory data being used by the memory banks on each gpu.

 

Combining two cards in SLi does not double the memory bus, but remember that you are splitting the workload between two GPUs when running in SLi.  Therefore it's highly unlikely that you will over saturate the memory bus on either card.

 

If I remember the formula correctly it looks something like this;  (math wizards feel free to correct if wrong   )

 

Clock freq (MHz) * bus width (bits)/8 * transfers per clock cycle (there 4 when using GDDR5) = bandwidth in MB/s

 

Frankly, I still think that you're totally hung up on the wrong part of the equation.  You really need to consider the cards in their entirety and not just think one solution is better than the other because of a larger memory bus.

 

I think that the Boss probably said it most succinctly, if you're going to make a purchase right now and don't plan on doubling your investment in the next few months, GTX 770s in SLi would be a splendid choice.  However, if you can swing a 780 right now and think that you can afford another in a few months, then go that route. 

[Braegnok]

 The 4GD5 GTX 770 SLI set-up would be my choice,.. you would be vary happy running @ 2560X1440 single monitor with them,..  

[wevsspot]

Maybe Niko should have just started a poll    and then made his choice based on the poll results.

 

SLi versus a single beastly card always opens up a can of worms and multiple pages of debate.  Without question twin GTX 770 4Gb cards in SLi will pounce a single GTX 780Ti or even a Titan.  I'm hoping that after two pages of comment and debate Niko will be able to make whatever decision is best for him.

 

I've already said it once, but I guess I'll repeat myself.  If I were spending my own money I'd get the two GTX 770 4Gb cards and call it done.  Regardless of what is in the pipeline for the next one or two gpu evolutions, it is going to be hard to trump a couple of GTX 770 cards that have an abundance of VRAM.

[ccokeman]

I have been running dual cards since I had a pair of 1900XTX cards using an external dongle to connect them. 

Since then scaling has improved tremendously when adding the second card. However AMD/ATI got lost along the way and are just now starting to get it figured out while the green team has had it figured out for a while. Higher levels of VRAM pay dividends when you start pushing the eye candy up in the latest games at high resolutions. Other than that I have not seen much of a difference at 1920x 1080 or even at 5760x1080.