Wednesday, December 17, 2014

GTX 970/980, More CUDA Cores Than Ever Before! (Proof)

When I first read about the GTX 970 and GTX 980, I was amazed at their performances given their prices. It was also the first time I was more than willing to get a second-tier card (GTX 970). But then I saw the CUDA core counts and my mind began to drift back to a GTX 780. I then realized that the 900 series actually offers more CUDA cores than what is being listed...

CUDA Cores
CUDA cores are useful for certain applications. There are many that take advantage of them and can help accelerate performance in said applications. Here is a list of some on NVIDIA's official site, and here is more on NVIDIA's site geared towards engineers. To most gamers, I highly doubt they consider this important, if they find a use for it at all (other than bragging rights). But for people like myself, who use products like Adobe Premiere Pro, CUDA cores can make all the difference.

Breakdown
This requires a breakdown to understand the reasoning why the GTX 970 & 980 would actually be a good upgrade from a purely CUDA cores standpoint. First, I will list some cards and their CUDA core counts:

GTX 480
CUDA Cores = 448

GTX 580
CUDA Cores = 512

GTX 680/GTX 770
CUDA Cores = 1536

GTX 780
CUDA Cores = 2304

GTX 780 Ti
CUDA Cores = 2880

GTX 970
CUDA Cores = 1664

GTX 980
CUDA Cores = 2048

Note: The GTX 770 is a GTX 680 in wolf's clothing.

Now, at first look, it would seem that there were no large leaps that would prompt a need to buy a GTX 970, depending on what you have now. And in fact, some leaps would be in the opposite direction!

I initially had a GTX 480 and didn't upgrade until I could get a GTX 680, which is an extra 1088 CUDA cores difference. But for me to jump to a GTX 970 would mean only 128 CUDA cores more... Definitely not the jump I had from a GTX 480 to a GTX 680, and certainly not what I expected from a GTX 970. At best, the GTX 980 would be better, albeit at a much larger cost.

Calculations
But wait, the numbers are lying to us. The Maxwell architecture claims that the CUDA cores of the GTX 970 & 980 are 40% more efficient! So we need to calculate all the cores, save the 900 series, for their new true values in comparison.

We leave the 900 series alone, as they are at 100% values. Because they are 40% more efficient, we subtract those two numbers to arrive at 60%. We then multiply any other series by 60%, because those are at most 60% as efficient as per one CUDA core from a 900 series. Or, each CUDA core in any other series is equal to 0.6 of its listed value.

If we do the math and multiply all the CUDA core amounts by 60% we get:

GTX 480
CUDA Cores = 268.80

GTX 580
CUDA Cores = 307.20

GTX 680/GTX 770
CUDA Cores = 921.60

GTX 780
CUDA Cores = 1382.40

GTX 780 Ti
CUDA Cores = 1728

GTX 970
CUDA Cores = 1664

GTX 980
CUDA Cores = 2048

The calculations make it apparent that the 900 series are truly a leap in CUDA cores if coming from a GTX 770 or below. If I happen to replace my GTX 680 with a GTX 970, I will get an additional 742.40 CUDA cores. Almost 70% of how many CUDA cores I gained last time. Which is a good increase, especially coming from the second best 900 series card (as of now). Trading up to a GTX 980 would net me 1126.40 CUDA cores, a bit more than my original jump!

GTX 780 & 780 Ti: The GTX 780 is not quite up to a GTX 970, but it is 281.60 CUDA cores away. I am not sure that I would consider this a big enough increase in order to take the plunge. It's really a toss up. If I were contemplating the GTX 980, then I would say it is worth it. As for the GTX 780 Ti, it should be better than a GTX 970, but not as good as a GTX 980. It obviously would not be worth the downgrade to a GTX 970, and in all honesty, I don't think the GTX 980 would be a smart upgrade either.

By Far
This the shortest article I have ever written to date. At first it was meant to be part of a post about why to get a GTX 970, but secretly all I wanted to do was write about this CUDA cores secret. There are very good reasons to buy a GTX 970, but I'll probably wait until I get one before I finish the original article.

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