GTX 980: First Thoughts or Impressions?

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3d-pangel
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GTX 980: First Thoughts or Impressions?

Post by 3d-pangel » 26 Sep 2014, 19:36

At 4Gb of memory and utilizing the Haswell architecture, the GTX 980 has an NVidia compute capability index of 5.2 (vs. 3.5 for the Kepler based cards or even the 6 Gb Titan). Also, the GTX 980 runs with less power than the 780Ti (the past go-to favorite) and therefore quieter and cooler (and presumably, longer life under load).

Therefore, for GPU calculations of the TFD simulation cache, is this "the card to have" for TFD?

Is a higher compute capability a good trade-off against the higher memory of the Titan or K6000 cards?

Dave

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Re: GTX 980: First Thoughts or Impressions?

Post by jascha » 26 Sep 2014, 21:25

For TFD it's safe to say that you should always prefer more memory unless you plan on running mostly small sims.
The time a fast GPU with less memory saves you is quickly lost when the sim has to fall back to the CPU before the GPU with more memory does.

3d-pangel
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Re: GTX 980: First Thoughts or Impressions?

Post by 3d-pangel » 27 Sep 2014, 00:23

Really confused by this because in previous posts, I thought that the higher compute capability, the better. With a 4Gb of memory and a 5.2 compute capability, I figured the GTX980 was the best of both worlds.

So I ask you (and this is an important question as the price difference is $500), which card would you choose:

1) Titan Black: 6 Gb of memory, 3.5 compute capability index, Cost $1000
2) GTX 980: 4 Gb of memory, 5.2 compute capability index, Cost $500
3) Your recommendation if not one of these two and not either the Titan Z or the K6000 (12 Gb of memory) as I can not afford those.

Thanks,
Dave

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Re: GTX 980: First Thoughts or Impressions?

Post by jascha » 28 Sep 2014, 09:04

Regarding "higher CC is better":
Whether or not a newer compute capability is better for a specific application depends a lot on both.
The CCs are made up of several processor features many of which have to be used explicitly by an application to yield any benefit.
TFD explicitly uses CC features up to 3.0. For the later CCs it may benefit passively from their increased cash sizes etc.

Either way, imagine a 980 and a Titan are doing a simulation-race - running the exact same sim. Let's say the 980 is 30% faster while the sim fits in it's memory. The Titan lags behind. Let's say at frame 130 the 980's memory is full and the sim has to fall back to the CPU. At this point the Titan is at frame 100 but it can keep going - about 5 times faster than the CPU. Therefore, by the time the Titan is at frame 130, the CPU is at frame 136. But the Titan can still keep going, since it has 50% more memory than the 980. So let's say it continues to frame 140. At that time the CPU is at frame 138, the Titan has taken the lead and it will continue to expand it until it runs out of memory.

These numbers are estimates, but the scheme should be clear.
It's like racing a fast car with a small tank versus a slower car with a larger tank and refueling is not possible.
Instead you have to continue on a bicycle when you run dry.
Who will win the race?

The bottom line is: the 980's advantage in speed will generally not be enough to work out a lead that lasts long enough to prevent the Titan from catching up after the 980 had to pass the torch to the CPU and before the Titan runs out of memory as well.

That is saying nothing about the price of the boards of course.
Whether the higher price of the Titan is worth it depends on how much time you can actually save on your projects (assuming there is more to do than TFD sims) and how quickly that costs amortizes.

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Re: GTX 980: First Thoughts or Impressions?

Post by 3d-pangel » 29 Sep 2014, 18:43

Jascha,

Thank you very much for taking the time to clearly explain the differences.

Better to stay with more memory as I would imagine that my sims will definitely push the memory requirements (one 16 second sim hit 25 Gb cache sizes). Hopefully, the Maxwell architecture finds it way to the Titan platform....but until then, I will stay with the Titan.

Dave

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Re: GTX 980: First Thoughts or Impressions?

Post by brasco » 04 Oct 2014, 14:41

Currently, a lot of the results say the 980 is a LOT slower than the Kepler cards in current CUDA based programs, it may be drivers since it's performing well in general Compute benches (OpenCL), so I'd hold off on jumping to a 980.
The 980Ti / Titan X specs are already leaking, so like you Dave, I'm looking forward to big Maxwell.

Also, I'd say to anyone DO NOT BUY A TITAN Z. Now, I don't normally tell people outright what to buy and what not to buy since it's personal choice but unless you're hugely space limited, this card is more expensive than two Titan Blacks ($2K vs $3K..) and they will completely smoke it in every aspect apart from power and space. The 12GB is split between the two chips, so therefore can't be used by anything at the same time (i.e. it's just 6GB everywhere it matters), the K6000 will give you that full 12Gb, but you pay the premium. So with the Z you're paying $1000 more for less performance, it still baffles me.

Really looking forward to CUDA6 features being more widely implemented so we don't have to worry about the memory cap as much.

cheers
brasc

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Re: GTX 980: First Thoughts or Impressions?

Post by Rus » 04 Oct 2014, 15:20

brasco wrote:Currently, a lot of the results say the 980 is a LOT slower than the Kepler cards in current CUDA based programs, it may be drivers since it's performing well in general Compute benches (OpenCL), so I'd hold off on jumping to a 980.
The 980Ti / Titan X specs are already leaking, so like you Dave, I'm looking forward to big Maxwell.

Also, I'd say to anyone DO NOT BUY A TITAN Z. Now, I don't normally tell people outright what to buy and what not to buy since it's personal choice but unless you're hugely space limited, this card is more expensive than two Titan Blacks ($2K vs $3K..) and they will completely smoke it in every aspect apart from power and space. The 12GB is split between the two chips, so therefore can't be used by anything at the same time (i.e. it's just 6GB everywhere it matters), the K6000 will give you that full 12Gb, but you pay the premium. So with the Z you're paying $1000 more for less performance, it still baffles me.

Really looking forward to CUDA6 features being more widely implemented so we don't have to worry about the memory cap as much.

cheers
brasc
I agree with you. Nvidia is just playing with us, haha. This "Titan Z" is made for those who do not fully understand how it works. There is no point on paying extra $1000 for ~10%(maximum) more performance than "titan" gtx 980, 970, 780, 770 etc.. etc..
It doesn't really worth it haha.
Ruslan Shaov
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https://vimeo.com/fluidfx

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Re: GTX 980: First Thoughts or Impressions?

Post by 3d-pangel » 06 Nov 2014, 19:17

An interesting comparison on the GTX 980 Ti vs. the Quadro K5200. Both have 8Gb and what makes this interesting is that it has some good detail into the 980 Ti specs:

http://www.game-debate.com/gpu/index.ph ... adro-k5200

I have been hearing some driver nightmares though with the latest Nvidia cards. Also C4D R16 is having some troubles with these drivers as well. Hopefully, these will be resolved because the 980 Ti looks very exciting. Anyone seen the specs on the Titan X? How do they compare to the 980 Ti?

Dave

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Re: GTX 980: First Thoughts or Impressions?

Post by brasco » 08 Nov 2014, 14:31

I have some doubts the Ti would be 8GB, it'd cannibalise their pro market (and Titan X). I would buy 4 on day one if that's the case though!
Any specs are just rumours from potential leaks at the moment so nothing is for sure.

And yes, drivers in regards to C4D have been terrible for the last 6 months, so many OpenGL crashes etc. I was doing fine on 344.11, no C4D crashes, but was getting errors in other programs (PS and AE) so I tried a newer one - just as bad, I reverted back to 344.11 and now I get problems with that one... No idea why! So all the way back on 337.88 with fingers crossed.


cheers
brasc

Rus
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Re: GTX 980: First Thoughts or Impressions?

Post by Rus » 10 Nov 2014, 21:38

I'm still on 340.52
I tryed all new drivers but i have issues with houdini's viewport. 340.52 works best for me right now. :(
Ruslan Shaov
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