oc vs stock gpu .. is it worth ?

Padone

I've seen a bunch of tests on the web and also a couple of discussions here in the forum. It seems overclocking a gpu only gets a 10% performance gain at most. At the cost of considerably more fan noise and power usage.

So what's all this rumor about oc ? If this is the case I can't really understand why oc cards exist at all ..

 

EDIT. On a second thought, it is true that oc cards usually have a better cooling system and psu extra connections. So if someone "underclock" it at normal specs, it may be a more reliable card for long rendering sessions .. Always if it is possible at all to "underclock" a factory oc card ..

y3kman

Use a software like MSI Afterburner.

fastbike1

Factory OC cards have GPU that measure better from a given batch. That is, they can run faster than the spec while being stable and remaining at the design operating temperature. A factory OC card isn't going to give more noise and more power usage because it's a better chip.

Factory OC cards do tend to have better cooling tham base cards but they all have the same base fan curve. Underclocking a factory OC cards makes no sense. You paid more money for the performance and the card won't be less reliable than the the base card. I think you need to be careful about the details on internet oc tests. The results you detail are probably from base cards that are user overclocked.

JD_Mortal

There is a LOT of OC headroom, for rendering and overclocking, because the cards do not use 100% of the GPU to render. They use a small fraction of the GPU, related to memory-management, compression, and cuda-cores. (Video-games use 100%, because GPU's use all the other goodies inside, to spit-out fast-renders. They do little actual calculations for photorealism.)

 

However, at some point, depending on cooling, the cards will auto-throttle down, on long runs. That heat builds-up, in time. No matter how well the cooling is. (They focus on GPU/RAM/VOLTAGE controllers, and the rest of the card just has heat build-up.)

 

Gains... You gain speed, with a major loss of efficiency. Which do you want... A $2.00 electric bill for 10 hours of rendering, or a $8.00 bill for 5 hours of rendering. 

 

My cards (3x Titan-Xp), barely heat-up, or throttle, within a 24-hour run. They are about 1/2 to 2/3 the heat and power-draw, when compared to running any video-game with max settings. Keeping them cooler, keeps them running faster, longer, and makes them less power-hungry on renders. (They are all reference-design fan-cooling, blower-fans.)

 

I don't overclock, because I am not into killing cards 2x to 10x faster, to save a few minutes of render-time. That is also why I don't use my 16 core, 32 thread CPU to help with rendering, unless I am rushing a rendering. (That shaves a few minutes off rendering too.) It is cheaper to just buy another card. (I still have two Titan-V's waiting for a Daz3D update, so it can see the cards as a valid rendering card. $6,000 paperweights, at the moment.)

Padone

Thank you all for the comments. I'm new to oc since I never considered it for rendering so far. I've seen other videos on youtube showing underclocking. It seems that underclocking a gpu only gets about a 10% decrease in performances but greatly reduces heat and power consumption. That's the opposite of overclocking. So I guess for long rendering sessions, for example where you leave the pc rendering overnight for animation, it may make sense to underclock the gpu.

These techniques of underclocking seems to be used also by miners to optimize overall gpu efficiency of power bills vs computation speed.