Something productive from "Is it forbidden..." thread

[tuckerkao]

Originally Posted by kriesel

RTX 3080 Ti is fast at ~4800 GHD/d in TF, but at ~93. GHD/day for PRP, LL or P-1, is comparable to a GTX 1080 Ti or RX 5500 XT or ~30% of an RX 6900XT or Radeon VII per https://www.mersenne.ca/cudalucas.php
I have multiple Radeon VIIs on a system served by a Celeron G1840, so yes it does not take much CPU to keep GPU apps going. Except when doing GCDs in P-1. I recommend about as many physical CPU cores as GPUs & HT so the GPUs are unlikely to wait for each other. Also >16GB of system ram if doing a lot of GPU P-1 on multiple 16GB-vram GPUs simultaneously.

Looks like I should get AMD Threadripper 5970X and AMD Radeon RX 6900XT, it's actually a bit cheaper of this combination. if I can finish most of the PRPs of M168,***,*23 within 2 years, then it'll be ideal.

Originally Posted by kriesel

I have multiple Radeon VIIs on a system served by a Celeron G1840, so yes it does not take much CPU to keep GPU apps going. Except when doing GCDs in P-1.

I'll focus on P-1 factoring for all the M168,***,*23 exponents that have been trial factored up to 2^77 with my current old machine now, so when I get my new PC, it'll be mostly PRPs and TFs of 2^77 to 2^78 remain.

[drkirkby]

Originally Posted by axn

TDP doesn't mean maximum power consumed by the CPU. A 165W TDP processor could easily consume 200W or more running flat out. Not saying that's what your CPUs are doing, but it is possible.

Also 12 sticks of RAM consumes a fair bit of power.

Yes, I realise the RAM could use a fair bit of power. That was an oversight not putting it on my list.

To quote from the Intel website

https://www.intel.com/content/www/us...rocessors.html

What is the maximum power consumption for my processor?Under a steady workload at published frequency, it is TDP. However, during turbo or certain workload types such as Intel® Advanced Vector Extensions (Intel® AVX) it can exceed the maximum TDP but only for a limited time , or

• Until the processor hits a thermal throttle temperature, or
• Until the processor hits a power delivery limit.

So the CPU would not use 200 W for a sustained period of time - only a limited period of time. I would have thought those limits were seconds or minutes, not hours.

There's no way of overclocking/underclocking the RAM or CPUs in my machine. I've got some Dell and IBM servers here, but the power consumption of them is frightening. They rarely get used. I've not tried them with GIMPS - the noise level makes it impractical to use them.

[Uncwilly]

Originally Posted by tuckerkao

if I can finish most of the PRPs of M168,***,*23 within 2 years, then it'll be ideal.

Stop attempting to make every thread about your pet range. Keep this up and see what happens.

[tuckerkao]

Roland Clarkson finished some of his exponents on Jul 21, 2021, wondering what type of machine is he using? Only 1 or several of them.
https://www.mersenne.org/report_expo...0376000&full=1

[retina]

Originally Posted by drkirkby

So the CPU would not use 200 W for a sustained period of time - only a limited period of time. I would have thought those limits were seconds or minutes, not hours.

I suspect that if you have good cooling then you can exceed TDP indefinitely.

If you don't care about efficiency or longevity then there is little to worry about when running it at full capacity, the CPU will throttle itself if things get too hot.

[M344587487]

Originally Posted by retina

I suspect that if you have good cooling then you can exceed TDP indefinitely.

If you don't care about efficiency or longevity then there is little to worry about when running it at full capacity, the CPU will throttle itself if things get too hot.

I thought I replied to that effect but must have neglected to hit send. Basically the link they're quoting from is intentionally vague and doesn't even mention generation, which is iffy as they've been adding more and more tiers of boost and guarantee over the generations as they've had to keep pushing limits further. For a start TDP for modern intel is for baseline all-core, it's a guarantee that if you have a cooler that can keep up with the TDP that the processor can perform at least to the baseline (unsure if they even include AVX/2 in this stat). There's a few types of normal boost that I believe are indefinite if conditions allow, and there's also timed boosts (PL1 and PL2 with tau for time) that far exceed normal limits if conditions allow. Motherboard manufacturers can also set tau to indefinite out of the box if they like, many did a few generations ago to boost their benchmark stats but I don't know if that practice continues.


Some of this may or may not apply to their specific processor, the model has been lost to the forum void.

[tuckerkao]

Originally Posted by M344587487

It's a guarantee that if you have a cooler that can keep up with the TDP that the processor can perform at least to the baseline (unsure if they even include AVX/2 in this stat). There's a few types of normal boost that I believe are indefinite if conditions allow, and there's also timed boosts.

With the better types of the cooling kits, the CPUs can usually reach the Turbo clock speeds which Prime95 will slow the milliseconds per iteration ratio if the CPU cores exceed the temperature limits.

Originally Posted by retina

The CPU will throttle itself if things get too hot.

I could even smell something when my CPU got to the extreme hot temperature once, but my PC survived, so I guessed it wouldn't be that critical of the issue as long as the condition got resolved quickly. Thus, I dusted the motherboard, the video cards, the PC case fans as well as the memory slots around the CPU area, then everything went okay.

I'm still wondering whether it's a good idea to install more than 1 Radeon RX 6900 XT on the same machine or not because they more get hot rapidly if stay too close with each other.