Question about intensity

[cneeper]

@bryan, since you mentioned intensity (in another thread)...

Being new to mining and to Sia, I've been trying to figure out exactly what "intensity" is, how it affects mining, why it is specified in a range up to I think it was 30, and why one might use different intensities for multiple devices on the same GPU card.

I have only one GPU card dedicated to marlin. If I'm understanding correctly, marlin --benchmark is telling me I have 18 "devices" with different names like "default", "m1p0", "m1p1", etc. on my card ranging from 3519 MH/s to 3727MH/s with intensities between 29 and 30. Should I be passing those intensities on my marlin.exe -I command line in list form? Right now, I'm just passing -I 30

I've found some references to it, but nothing definitive or particularly useful so far. Can you (or anyone) explain or provide a link to a good explanation?

Thanks!

[bryan]

@cneeper short answer would be for your stability. For example if you tried to run an old GTS 450 that only gets 50 mhs it would only be able to run 5 intensity or system crash.

But it sounds like with that many devices you're prolly good to go at the max.

[chrisscott666]

i dont understand intensity, im running 4 1080 ti gpu's and running intensity on 21, will i get more coins if i put it up to 30? or will the program crash?

[bryan]

@chrisscott666 If you turn it up your hash should increase slightly maybe 20-50 per card. But if your system can't handle it it will definitely fail. Mine usually go to a black screen.

[chrisscott666]

what sort of spec do i need to run at 30? it has rizen 7 3ghz 8 core and 4 gfx cards?

if i over clock the cards would that help with intensity? even 10 coin per card per day over a year adds up ;o)

[cneeper]

While I have 30+ years of experience with computers and I'm not new to digital currencies, Sia is my first experience with mining. Is "intensity" a siacoin specific concept, an Ethereum-derivitive concept, or a concept common to all digital assets?

I've still yet to figure out what it is really. On the surface, it seems to be an artificial limitation or delay introduced into the mining software to avoid overwhelming the hardware. But that doesn't make sense to me because I'd expect that we'd want the software to push the hardware as fast as it can, allowing the hardware to be the limiting factor.

Still looking for a more technical explanation for the concept...If anyone has any links to get me moving in the right direction, that would be greatly appreciated! My Google-fu has failed me.

[cneeper]

@chrisscott666, I'm running a single air-cooled (stock) Nvidia Titan Xp (GP102-450-A1 processor, 3840 cores, 12,288MB GDDR5X). It's default clock is 1405MHz (1582MHz boost). Without any special cooling, I have it overclocked to 1923MHz at 862mV right now, where it seems pretty stable. I've pushed it as high as ~1981MHz, but am less certain of its stability at that rate. My temperature is a relatively comfortable 66C and I suspect I may be pulling too much power from my power supplies at higher clocks, so I could probably go higher if I put some effort/money into hardware (better cooling, better power). This card seems to have 18 devices, according to marlin --benchmark.

With this setup, I have my intensity at 30, which, from what I understand may be max. I seem to average somewhere around ~3500 MH/s in a fairly wide range. I've only been mining about 8 days so far, but I seem pretty stable. That being said, however, I've noticed a developing pattern where my miner crashes about once per day. The oddity is, however, that it seems to crash around 4am (local time), so it may not necessarily be related to overclocking or even intensity being too high. Still monitoring and evaluating that one... I just modified the batch file that launches the miner to start logging crash times and then restart the miner...trying to get more data on what's going on.

So, if a lesser GPU requires a lesser intensity to be stable, does that mean that maxing out the intensity at 30 on a better GPU becomes an artificial limitation introduced by the mining software? Questions like this are why I'm trying to learn what intensity really is. Many people are fine with generalities, but to me the Devil is always in the details!

[chrisscott666]

all very interesting stuff, my cards are factory clocked but still have plenty to give, im away at the moment as i work offshore and only had 1 day to get it up and running, and be stable for the two weeks I’m away so i didn’t play about too much. I have 2 1000 watt power supplies on 4 cards all with 11mb so i should have plenty of juice, when I’m home ill raise it to 30 and see if it has a effect and then play with the clock speeds.
Engine Clock
Base: 1608 MHz
Boost: 1721 MHz

But can go up to 2000mhz I’m lead told. i will see how playing with it changes hash rates
I have an open air rig so temps are around 65c at full tilt
Mine was crashing at first till I noticed windows power save was on and it wasn’t crashing it was saving power lol
A auto restart for the miner that would be great for temp loss of internet or power when I’m away as my wife would only have to turn it back on, rather than me try to explain how to restart the miner to her lol

[2xjO9M3P]

@cneeper "Is "intensity" a siacoin specific concept, an Ethereum-derivitive concept, or a concept common to all digital assets?

I've still yet to figure out what it is really."

Old quote from author of CGminer:
Intensity is the amount of work in one go the GPU has to do before it can return its results. It needs to be large enough to keep the device fully utilised yet not so overloaded that the device becomes unresponsive. The faster the GPU, the higher the sweet spot is.

I do believe that for some algorithms GPU RAM can potentially be a limiting factor for how high intensity you can run.

Edit: and no, it's not specific to SIA mining. Most, if not all, miners have some sort of intensity setting, though implementations may differ.

[xurious]

Intensity is for mining via GPU. All coins that can be mined on a GPU, use intensity.

The quote from CGminer is spot on, to exactly what it is.

Intensity is how much work is sent to the GPU. It's based off a power of 2. Int 21 is twice as much work as int 20.

[cneeper]

@xurious @2xjO9M3P Thank you both for your explanation. This makes sense to me. I went back and read the original thread for that quote to glean some more context. If memory serves, I don't think Sia is GPU RAM intensive, so I've actually underclocked the 12GB RAM on the card to reduce power consumption. I didn't see any significant impact on hash rates.

So to extrapolate what I've learned to answer one of my questions, if I=30 is truly the optimal setting for my GPU (I'll have to play with it a bit to find out), then it stands to reason that if I happen to have a futuristic GPU (say, maybe next year's model) that is twice as fast as this one, then I=31 might be the optimal setting. However, marlin doesn't (currently) accept I=31, so it seems the mining software itself would become a limiting factor by not fully utilizing the devices.

I think in a few days I'll start playing with the intensity to see how it affect my hash rates.

Thanks all!

[xurious]

It's not ram intensive. I have my memory underclocked by 500MHz.