Help Identifying A Possible Bottleneck (VRAM VS GPU Usage)

[MiRai]

I'm trying to figure out how a game (any game) might handle excessive amounts of video RAM when there's a lot available. I realize that different games may handle this differently and there is no single absolute answer, but I'm trying to get a general consensus on what people think about my situation.

I currently have three GTX 580 3GB models in 3-way SLI and I can practically max their GPU usage and push about 2.8GB - 3GB of video RAM because I love to force on 4x SGSSAA (or 8x SGSSAA, when possible) on the games that I play. Now, at the moment, I feel like I'm more limited by the GPUs themselves rather than the amount video RAM because the GPU usage is usually no less than 80%, and I'm guessing the games I play might just be filling up the video RAM because I have a lot of it.

Assuming I was to purchase two GTX 780Tis I would have about twice the GPU power I currently have today, but the same amount of VRAM (3GB). Just as a rough estimate, let's say with the same settings I'm using today, I'd be using about 60% of the GPUs and the same amount of video RAM, but...

Would it be likely that I'd see an increase in performance with an upgrade to some 780Tis? I'm guessing 3GB of video RAM would eventually be a limiting factor at some point if it isn't at the moment, but is it possible that the games are just sucking up the video RAM because they can?

I'd rather not have to purchase two Titans at full price this late in their life (for access to 6GB) and was hoping I could save some money with some 780Tis. I'd also rather stick to nVidia GPUs for the time being.

Thanks!

 

[FalseChristian]

Don't worry about vRAM usage by older games! I still like to play Quake with the Darkplaces mod (it looks incredible!) and it only uses 64MB out of the 2GB I have on my 2GB GTX 650 Ti BOOST.

You have 3 GTX 580 3GB! Not 2 but 3! And did I mention that they're 3GB? LOL! You don't have to upgrade until at least AMD's and nVidia 20nm GPUs come out in 12-16 months!

If I had your system I'd throw mine away!LOL!

 

[Stuka87]

If you see 90%+ of memory usage you will most likely notice hitching. Are you seeing any sort of jerks in game play?

Running SGSSAA at 4x or 8x is going to consume a ton more ram than the base game ever would. Yes more memory will be used if its there, but not so much that it actually hurts itself.

I would have to look to see how much faster 2 780Ti's are compared to three 580's are. They will be faster, just not sure how much.

Honestly, I would just lower your settings a bit. And wait for 20nm.

 

[MiRai]

If you see 90%+ of memory usage you will most likely notice hitching. Are you seeing any sort of jerks in game play?

The only time I'm noticing any stuttering or jerking is when the GPU usage is 90%+ which is why I'm leaning toward the idea that the GPU itself is actually the bottleneck and not the VRAM.

I would have to look to see how much faster 2 780Ti's are compared to three 580's are. They will be faster, just not sure how much.

Honestly, I would just lower your settings a bit. And wait for 20nm.

I already ordered two 780Tis and they arrive tomorrow night, so I'll be doing some testing over the next few days after that and I was planning to revisit this thread with the results. If they're not up to par I would most likely just send them back, eat the restocking fee/shipping, and just wait it out.

 

[MiRai]

Just to revisit this and give some closure for anyone who might stumble upon this at a later date...

Two GTX 780Tis in SLI use the same amount of VRAM and give me much better performance than the three GTX 580 3GB cards. So, I'd have to say that the game(s) were just eating up VRAM over time because it was available.

I will also say that it feels good to have upgraded after 2.5 years.