Another graphics card question

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Mike in Rancho
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Another graphics card question

Post by Mike in Rancho »

So with prices starting to come down, I've begun considering replacing the mostly-pathetic GTX 745 in my desktop. As maybe the best bang for the buck, I have started leaning towards perhaps an RTX 3060ti. Not quite at MSRP yet, but perhaps soon. Also, I think Nvidia and AMD should be releasing the next gen cards this year, hopefully in months, which might also help with prices on GPUs.

I think I recall that past threads directed us to the Open CL benchmarks for ST's GPU performance? Although those benchmarks and various gaming/speed rankings and benchmarks don't exactly match, they are often close and the 3060ti seems pretty decent as to all of them. Though of course it's no 3090.

One thing I just read about the 30xx series cards though, at least after a certain manufacturing date, is that they implement LHR as an anti-cyrpto feature. Not that I know anything about crypto, but since ST's GPU is an offload when appropriate for number crunching and calculations, is ST affected by LHR? And if so, enough that one should drop back to a prior gen like 20xx?
hixx
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Re: Another graphics card question

Post by hixx »

Hi Mike,
sorry I don't know anything about the crypto restriction piece neither, but what is really a must for ST is larger VRAM. The VRAM has fast access so ST is able to push & pull data more quickly. In that light it might be wiser to go for a middle of the road GPU with max VRAM amount rather than a top end model with just a standard "graphics task" VRAM. On my Apple M1 Max I have the binned 24-core GPU version and I did some GPU testing with some ST modules:
WIPE showed GPU around 20% AVG, peaking up to some 90% or so
HDR is another long-runner with the GPU around 10% loaded mostly and some bursts up to 90%
SVDecon has a huge amount of GPU bursts around 80-90%
The one GPU hog is SuperStructure though: it fully loads the GPU 100% in 4 phases towards the end of the calculation

Of course this is Apple not NVIDIA, but I assume You should be fine with the 3060 and enough VRAM. Most calculations have large parts leaning on the CPU anyway, so the amount of calculations when GPU becomes a limiting factor is very minor. Even my 2015 imac with an aged AMD390 R9 had a decent GPU ST performance compared to my M1 Max Usually The limiting factor is rather the VRAM
Clear Skies,
Jochen
Mike in Rancho
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Re: Another graphics card question

Post by Mike in Rancho »

Thanks Jochen,

My current card has 4GB of VRAM, and any new one should have more, possibly least 8. However, when I use various performance monitors, I haven't really seen ST use much of the VRAM at all.

A faster CPU would probably speed things up more for ST overall, but that won't be happening any time soon. A GPU upgrade would help with a number of things, and if it gives ST a little boost also that'll be icing on top.

A 3060 ti does seem to have a good Open CL benchmark - though whether that was measured on the initial FE/reference card before all 30xx series implemented LHR, I don't know.
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Re: Another graphics card question

Post by admin »

I think the Low Hash Rate cards work by detecting specific patterns in behavior. Those patterns apparently have to do with lots of random memory location access. I don't think this should impact StarTools much, though it is possible something like SVDecon may get caught in this, as it does switch/interpolate/jumps between a few thousand different point spread functions during decon. I think you should be safe, but I can't say for sure.

Jochen brings up a good point about VRAM. Large datasets will require *a lot* of VRAM. Depending on your future needs (big mosaics? massive JWST datasets?), this may or may not be something to take into account.
Ivo Jager
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Mike in Rancho
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Re: Another graphics card question

Post by Mike in Rancho »

Thanks Ivo!

Interesting that a card might think SVD is...mining. :lol:

However, by VRAM I presume you and Jochen are talking about the GPU card's onboard memory? i.e. Video RAM...not virtual?

With my current 4GB GPU, I've run various monitors and I don't think I've seen it go much over 1GB used of the dedicated GPU memory. One was just for a split second (perhaps in Wipe or AutoDev, I forget) to maybe 1.2 gig, and then when I ran SS on a large file it used 0.9 gig of the GPU RAM for quite a bit. Pretty large file too.

Now, plenty of the mainboard's 32GB of RAM was used by ST throughout processing, but why so little of the GPU RAM? And if ST will only use 1GB of the 4GB I have now, would there be any point to GPU with 8GB? Other than the DDR6 might be faster, and that so many new GPU's just happen to come with a decent chunk of RAM...

:?:

Is is possible I have something set wrong in Windows? Or that I am using the wrong diagnostic monitors? I tried the GPU performance section of Task Manager, GPU-z, and the statistics graphs of MSI Afterburner. Not all at the same time of course.
hixx
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Re: Another graphics card question

Post by hixx »

Hi Mike,
yes Vram means Video RAM, not virtual. VRAm ist a RAM Type with much faster throughput than normal RAM. For ST calculation You' want it to hold a 3 channels of a full image ( e.g 24 MB x 3(RGB x2 /(32 bit) =144 MBs multiplied by a number of copies e.g in modules using iterations. Also You'll need actual "Video" Memory on top to support the graphics. That stacks to a pretty large number, but with 8 GB I suppose You'll be OK for 99.9% of all calculations. If You VRAM is running out, it will push & shove portions of data between VRAM an normal RAM or SSD, so Your limiting factor would become the bus architecture, RAM or SSD. I remeber there is a thread somewhere around here on the forum regarding VRAM,
Clear Skies,
Jochen
Mike in Rancho
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Re: Another graphics card question

Post by Mike in Rancho »

Thanks Jochen,

No my point was that my VRAM is not even close to running out, even on the old school GPU. I did momentarily get it up to 1.5GB used the other night working on my mosaic, which is like two 26 megapixel files stitched together. But it was an HOO. Maybe when I add a third channel to make it SHO? Or if I had an NBAccent file?

Oh well, I'll keep an eye on the monitors, but with the stuff I do I haven't seen even my 4GB VRAM get threatened. But a newer card is likely to have faster speed overall, plus more and faster VRAM.

I suppose I do have to wonder a bit though if my "new to me" i7-6700 is hindering ST. At least for unbinned mosaics and extra large files. For my normal resolution processing things don't seem problematically slow.
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