Beginner question on VRAM for Discrete GPU cards

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Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 2:42 pm

Hi guys,

Hopefully this isn't a super redundant question, but I'm looking to build a new desktop (mostly for gaming and some video editing, plus schoolwork) and I'm noticing that the videocards being recommended by TR still mostly come with just 1GB of VRAM. Obviously the processors and architecture have improved vastly since I last built a computer in 2009, but I'm surprised that the memory hasn't increased proportionally. I remember how GTA IV gobbled up VRAM at even modest texture detail levels, and I was wondering if I would be better served by spending more money to buy a 2GB graphics card. I'm not a power FPS gamer or anything, but I'd like to be able to run older games (like GTA IV or New Vegas) very well and have some runway for the next 2-3 years of PC games. Any advice or thoughts would be highly appreciated.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 3:06 pm

Resolution of your screen is the biggest consideration.

As you go up in resolution, the pixels increase faster(non-linear) and require more memory.

I'd go 2 for anything over 1920x1080 for sure. Of course, it all depends on what you want to spend.

Sweet spot on the cutting edge price to performance is something like the AMD 7950 which has 3. But since you asked about one, I'm guessing you are looking at lower than $250-$300. :wink:

So, A 650 TI with one or 2? Yeah, I'd go with the 2 for the $20. But of course, they assume that the lower cards are not going to be pushing high end games on high end screens, so the memory is less for a reason. Step up to the 660TI and the memory and performance/ price increase is substantial.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 3:19 pm

The amount is only one variable in the whole equation. You can find low end cards with slower GPUs boasting 1GiB or even 2GiB RAM configurations, but that does not mean they are fast enough to utilize all that RAM. Also, we seem to be slowing down in terms of game resolution at around 1920x1080/1200. Sure higher levels of AA will drive up memory bandwidth, but resolutions are not going up like crazy. The industry are trying to lure us with new stuff like 4K video, multimonitor gaming, and 3D, but the majority is still leveling off at 1080p.

BTW, I'm not sure about your assertion about "videocards recommended by TR still mostly come with just 1GB of VRAM". Looking at the most recent System Guide, only the Econonbox suggestions of the 7770 and 7850 1GB cards are equipped with 1GiB of onboard memory. Others are already 2 if not 3 gigs.

You may have a lower than TR average budget (i.e. Sweetspot) so your "band" of video cards is skewed a bit. It may be more helpful to let us know your budget.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 3:41 pm

Thank you both for your responses. I guess I should have kept going in the guide, I kind of stopped off at the EconoBox before asking this question. :oops:

My budget is actually pretty flexible - probably want to keep it under 1500 for the whole build though, excluding monitor & OS. Otherwise it would be a different sort of discussion with my wife. :)
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 4:16 pm

The value of the 7950 right now is hard to beat. I don't know what programs you use for video editing but Premiere CS6 supports opencl (along with photoshop) and gives a nice performance boost.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 4:33 pm

Not to throw a monkey wrench into everything, but the size of the memory pipeline also affects performance in some instances. That's why I like AMD cards right now, they may not be quite as power efficient, but the 7850's and up have 256-bit or larger memory interface which allows them to deal with AA better, and they have much better GPU-compute performance than Kepler for what it's worth.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 5:25 pm

DPete27 wrote:Not to throw a monkey wrench into everything, but the size of the memory pipeline also affects performance in some instances. That's why I like AMD cards right now, they may not be quite as power efficient, but the 7850's and up have 256-bit or larger memory interface which allows them to deal with AA better, and they have much better GPU-compute performance than Kepler for what it's worth.


Just remember that Nvidia made their memory pipeline a little 'wider' with Kepler- Kepler also uses less total VRAM for the same applications than Fermi and GCN. As for compute, well, it matters to a very specific set of people, and Adobe applications aren't on that list :).
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 5:36 pm

DPete27 wrote:Not to throw a monkey wrench into everything, but the size of the memory pipeline also affects performance in some instances.


Yeah, the GT 640 is one to avoid for this reason. You can't narrow it down to a single value - so look at the benchmarks Some 1GB cards beat 2GB cards, some 2GB cards beat 3GB cards. There are enough benchmarks here (let alone the rest of the web) to make a decision on a particular model without worrying about how much RAM it has - the value scatterplots aren't a bad place to start looking.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 9:46 pm

Airmantharp wrote:Just remember that Nvidia made their memory pipeline a little 'wider' with Kepler

Can you explain this statement a little more? Even as low as the GTX 460/560 had a 256-bit interface. Now with Kepler you don't go above 192-bit until you get to the GTX 670. Maybe I don't understand the relationship between available VRAM and the memory bus width as well as I thought.
My understanding is: the wider the memory bus, the faster data can be transferred to and from the VRAM. Available VRAM is how much info you can store at a time. Seems to me that if Kepler is so much more memory efficient, then it makes sense that you can get away with having less available VRAM. But you should still need enough "lanes" to transfer data into and out of the VRAM fast enough for the application to use it; otherwise you still end up with a bottleneck. The article I linked shows that bottleneck.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Wed Nov 07, 2012 11:08 pm

DPete27 wrote:
Airmantharp wrote:Just remember that Nvidia made their memory pipeline a little 'wider' with Kepler

Can you explain this statement a little more? Even as low as the GTX 460/560 had a 256-bit interface. Now with Kepler you don't go above 192-bit until you get to the GTX 670. Maybe I don't understand the relationship between available VRAM and the memory bus width as well as I thought.
My understanding is: the wider the memory bus, the faster data can be transferred to and from the VRAM. Available VRAM is how much info you can store at a time. Seems to me that if Kepler is so much more memory efficient, then it makes sense that you can get away with having less available VRAM. But you should still need enough "lanes" to transfer data into and out of the VRAM fast enough for the application to use it; otherwise you still end up with a bottleneck. The article I linked shows that bottleneck.


I put it in quotes for a reason- it's not physically wider, rather, they made the whole GPU more efficient, so that it both uses less memory for the same job and by extension less memory bandwidth; and it has gobs of memory bandwidth.

When people go hating on Kepler for it's 256-bit bus, they're ignoring Nvidia's advances in efficiency. Memory bandwidth is not a problem for this GPU.

Also, you're posting on a legitimate review site; please reference one instead of an advertising agency. Using Tom's does not add to one's credibility.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Thu Nov 08, 2012 12:42 pm

Airmantharp wrote:Also, you're posting on a legitimate review site; please reference one instead of an advertising agency. Using Tom's does not add to one's credibility.

Ugh, I'm getting bashed again for using Toms. Look, I don't like them any more than the next guy, but they do still have good ideas once in a while, even if you have to wade through a sea of dung to find them. I would rather use anybody except Toms to prove my point in any case, but for this one, Toms was the only one that actually did the test.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Thu Nov 08, 2012 2:51 pm

One more small point to bear in mind. The graphics memory gets mapped in alongside the system memory. This means that, if you're running a 32 bit OS, a 3 GB graphics card will leave you with just under 1 GB of memory space for everything else. Not particularly desirable.

If you're running a 64 bit OS, this isn't an issue - even the earliest AMD64 processors had 40 bits of address space; 1024 GB of RAM space should be more than sufficient for most home needs (512 GB in the upper half, 512 in the lower half.)
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Thu Nov 08, 2012 3:45 pm

axeman wrote:graphics memory speeds continually go up as well. some newer cards have narrower memory bus, but not necessarily less memory bandwidth.

Memory bandwidth according to TR = 144 GB/s for the 660Ti and 240 GB/s for the 7950 for example. Also, the 650Ti and 7850 1GB come in at 99GB/s and 154GB/s respectively.
Since TR tests similarly performing cards with the same level of AA (usually 4x) the differences shown in their articles are directly comparable obviously. But that's not saying that an AMD 7xxx card with higher memory bandwidth can't cope with higher levels of AA better than a Kepler card. In fact, if AA is reduced below 4x as used in the TR articles, we can probably expect Kepler cards to show slightly larger fps gains than AMD cards. That's all I am trying to point out. I'm trying to learn here too. I also have no clear cut solution to the GPU performance cutoffs at which 1GB / 2GB / and more VRAM is optimal.

Back to the OP's question. I think a 7850 2GB card for just under $200 would offer you excellent performance for the next 3 years. That card sits between the GTX 650Ti and the GTX 660. In the end, AMD and Nvidia offerings are appropriately priced for their average fps performance while Nvidia cards have a slight price/performance edge in TR's 99th percentile plots. If you can afford the extra $20 or so, going with a $210 GTX 660 is the highest I'd go before the price/performance curve starts leveling off. Not sure where that falls with respect to your budget. Make sure you consider games bundled with various graphics cards when purchasing. If it's a game you might buy anyway, a bundled game with a graphics card would significantly affect the value proposition. The 7950 obviously falls in this category with its 3 bundled games worth roughly $150 if they're all high on your wishlist.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Thu Nov 08, 2012 7:54 pm

What DPete27 said- at ~$200 you've basically leveled off what's needed for 1080p. After that you're paying up for eye candy.

With respect to memory bandwidth- the Kepler GTX600- cards have lower theoretical bandwidth, but make much better use of it than prior Nvidia cards and all AMD cards. They may still have a deficiency in higher levels of AA, but it's difficult to attribute that to any one thing.

On the usefulness of AA- I haven't seen a situation where you can really get away with running a current game at it's highest settings and with 4xMSAA while keeping frame-times anywhere near 16.7ms (for smooth 60FPS) in the 99th percentile. It's nice to have, but the cost is so very high, and the hit to your wallet for that one bit of image quality is usually tremendous- and it gets far worse when you exceed 1080p.
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Re: Beginner question on VRAM for Discrete GPU cards

Postposted on Thu Nov 08, 2012 9:14 pm

Airmantharp wrote:On the usefulness of AA- I haven't seen a situation where you can really get away with running a current game at it's highest settings and with 4xMSAA while keeping frame-times anywhere near 16.7ms (for smooth 60FPS) in the 99th percentile.

I completely agree. For the GTX 660Ti and below, the "poor AA capability" is probably a moot point in modern titles for this exact reason. AA is the last thing I increase if I have some extra fps's to use up. With my 6850, that means I rarely touch it. Just wanted to throw it out there though.
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