What is the real difference?

[Johnny Baker]

In shopping for a good graphics card, for my pc build, I have run across something I can't quite figure out. I notice that on cards that carry 4 gigs or less of memory, it's a 256 system and on the cards that carry 6 or more gigs, it's a 512 system and everything else seems to the same, including the prices, LOL. I mean it's not like you get much of, if any, a price break on them.

Thanks for your comments.

Johnny

 

[Gallarian]

So your question is what is the difference between a card with 4GB of VRAM compared to the same card with 6GB+ of VRAM aside from the difference in VRAM quantity?

If so, there are none. One just has more VRAM...

 

[Epicness937]

really it is what he said you only need more vram for video editing/rendering and 4k and such

 

[geofelt]

It is fruitless to select graphics cards based on specs. The mix of specs is selected to meet a given price/performance target.
How the specs are used will differ from amd to Nvidia.
And, even across the product line.

Aside from benchmarks of YOUR games, the best single spec to determine performance is....
PRICE.
You get fair value per dollar from most cards.

VRAM has become a marketing issue.
My understanding is that vram is more of a performance issue than a functional issue.
A game needs to have most of the data in vram that it uses most of the time.
Somewhat like real ram.
If a game needs something not in vram, it needs to get it across the pcie boundary
hopefully from real ram and hopefully not from a hard drive.
It is not informative to know to what level the available vram is filled.
Possibly much of what is there is not needed.
What is not known is the rate of vram exchange.
Vram is managed by the Graphics card driver, and by the game. There may be differences in effectiveness between amd and nvidia cards.
And differences between games.
Here is an older performance test comparing 2gb with 4gb vram.
http://www.pugetsystems.com/labs/articles/Video-Card-Performance-2GB-vs-4GB-Memory-154/
Spoiler... not a significant difference.
A more current set of tests shows the same results:
http://www.techspot.com/review/1114-vram-comparison-test/page5.html

And... no game maker wants to limit their market by
requiring huge amounts of vram. The vram you see will be appropriate to the particular card.

 

[Johnny Baker]

Thanks for getting back to me this quickly. It's not about the # of gigs on a card but the system classification(s) of 256 & 512. You find 256 bit with 4 gig and smaller cards and 512 bit with cards that are 6 gigs or more. That is what the question was about.

 

[TJ Hooker]

I believe you're talking about the bus width. It's a measure of how wide the interface is between the GPU and memory. Wider bus means higher bandwidth, which means the the GPU can access info stored in VRAM faster (bandwidth also depends on memory clock speed). And it's not a rule that 4 GB or less is 256 bit and 6+ is 512 bit. For example, the GTX 980 ti has a 384 bit bus with 6 GB memory, GTX 960 has a 128 bit bus and 2 or 4 GB memory.

I honestly wouldn't worry about trying to compare bus widths between cards. As was mentioned earlier, you're far better just looking at benchmarks to try and figure out performance.

 

[Johnny Baker]

It was just a question that has bugged me for some time and was thinking it may be important. Thanks all, I appreciate it.

 

[TJ Hooker]

You're not the only one who gets distracted by bus width. I remember people complaining about Nvidia's Maxwell cards (GTX 9xx) having narrow bus widths compared to the previous gen and similarly priced AMD cards. But considering that a GTX 960 with a 128-bit bus performs similarly to a R9 380 with a 256-bit bus, and a GTX 970 performs similarly to R9 390 with a 512 bit bus, and that Maxwell cards handily outperform their previous gen equivalents, it's obvious that simply comparing bus widths is not a reliable way to judge performance. Same goes for just about any other paper stat, like core count, frequency, etc., unless you're comparing between cards with the same architecture (e.g. comparing a 970 vs 960).

 

[Johnny Baker]

10-4, I will definitely leave all the finer details to those that know more than me but, I now have an idea about this topic. Thanks.