Hello guys, I was wondering.. is there any reason still crunch on CPUs? I have notebook. Even if my notebook is gaming machine heat could be a problem. I am crunching on GPU only (thx 2 you guys for advice how to do it) which keeps GPU and CPU cool. But I wonder.. I have quadcore Core i7. Should I use sometime even CPU computing or still keep GPU (GTX 765M)? CPU can handle 4 thread at the time (yes, it has HT technology but i reduced it only to 4 threads because of heat) and GPU just one. GPU takes about 15-20 mins to complete task, CPU about 2 h and 10 minutes but 4 tasks. So I wonder.. if I should even use the CPU or not.
Hm?

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The choice is yours, you could always just use only 50 % of your chip(this can be found under the tools tab, computing preferences of the BOINC manager. Just change use at most to 50% and it will only use 2 of the 4 cores.) Then, 1 core powers your GPU and the other crunches, that should reduce any wear and tear on your chip. It should always help with the Temperature issues. Anytime you use a laptop, it's a good idea to either use a cooling pad or make sure there is plenty of space underneath it for cooling. Obviously the GPU is going to be much faster.

I made a conscious decision at one point to only have the GPUs do the crunching in my main rig. I figure it is the most efficient use of my electricity, as the CPU in comparison is not very efficient at all.

As Zalster says, it is your choice. If you are going for maximum crunching at any cost, use the CPU and GPU. If you are looking for efficiency vs the cost of electricity, I find GPU only to be a fine compromise.

Thx. But you did not fully answered;) But for sure it's the way let the BOINC use 1-2 core. Sure.


Heat is the issue everytime. I have Alienware 14 which has supreme cooling. But even then.. Intel Cpre i7 4800QM has TDP 47 W and for 14" laptop..it's quite a lot. Cooling pad did not help these days so much - actual laptop has a heat shileds (to not burn you legs) but then.. cooling pad is not helping much. And successfully cooling such a CPU and GPU is a challange everytime.

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mherr170 - you are thinking like me - i have same opinion..that CPU computing is no longer as efficient. But I want hear opinions of others. Perhaps one prove me wrong. But yes.. my goal is to compute as much as I can but effeciently. So GPU is looking to be only way. Now I am running 4 tasks on my CPU and it is almost 2 hours and task is not completed:( I want compare points for such tasks. If even points will be greater for GPU..then there is no reason to continue on CPU.

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mherr170 - you are thinking like me - i have same opinion..that CPU computing is no longer as efficient. But I want hear opinions of others. Perhaps one prove me wrong. But yes.. my goal is to compute as much as I can but effeciently. So GPU is looking to be only way. Now I am running 4 tasks on my CPU and it is almost 2 hours and task is not completed:( I want compare points for such tasks. If even points will be greater for GPU..then there is no reason to continue on CPU.

Not true, there are VLAR tasks which ar CPU only.

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is there any reason still crunch on CPUs?

One reason I have found is that some projects do not HAVE any gpu capabilities. I let them have the cpu time, and SETI gets the gpu time.

On my laptops, I only run those cpu-only projects (because the gpu creates too much heat all by itself crunching), and I use a limiter to be sure the laptop doesn't get too hot. This lets them crunch harder when it is cool (over night, rainy day, ...), but throttle back when it is mid-afternoon, 98 in the shade, and no airconditioning.

Some quick figuring looks like in that ~2hrs you can do 7 GPU units, and 4 CPU?

So the GPU is more efficient, but not by a HUGE margin. If the CPU is only running 4 tasks its power use will be lower. Not sure of the exact numbers, but it wont be anything close to it's TDP. If you could run the 8 threads on the CPU you might have a ratio of 7 to 6?

But because it's a high power laptop, cooling is going to be an issue. On a desktop you can simply bolt on a bigger heatsink, and a couple more case fans, and open the gates. On a laptop, not so simple. Most applications wont run the CPU AND GPU both at 100% for extended periods. Gaming? You might be 100% on the GPU, but only using a couple of CPU cores. Apps that max out the CPU probably leave the GPU alone. So it's likely they have cut corners and assumed that both chips wont run at 100% for extended times? They probably share a common heat pipe, sink and fan assembly?

So in your case it makes sense to throttle the slightly less efficient CPU to keep the heat down. In a desktop machine a multicore CPU can generate a similar amount of work to a cheapo GPU. Cooling isn't an issue, so it makes sense to run both. My old "Cheap n Cheerful" rig has a Q6600 and a GT630-III card. Both can earn about 2,500 RAC, although the GPU would be using less power. But a Q6600 is still worth running in my opinion. But it was easy to fit an extra exhaust fan to my 3/4 tower case.

Ian

I run 3 I7's. One is a 920 with a GTS250. The other two are 3770 with GTX550 Ti's.
Currently the I7 920 is doing stock MB only with HT off. The other two I7 3770's are running HT on but just 7 cores to feed the GPU's.

You could allways do your own test. Try just running you GPU and see what your RAC ends up after a month. Then turn on 4 cores. And waite. Then turn on HT and run 7 or 8 cores.

If you have heat issues. Maybe you need more or better fans. Or a bigger case, Or clean out the dust bunnies.

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Old James

Here's two i5 2400 rigs,

http://setiathome.berkeley.edu/show_host_detail.php?hostid=7046001

http://setiathome.berkeley.edu/show_host_detail.php?hostid=6271752

Not bad for rigs working only on CPU power.

Cheers.

If you have heat issues. Maybe you need more or better fans. Or a bigger case, Or clean out the dust bunnies.

But it's a laptop. With a desktop you can easily improve the cooling relatively easily. Laptop, not so simple.

Ian

I want to also second Ianab's comment. Your CPU is pretty good. If it only takes 2.5 hours or so to complete a task, that isn't too bad. Mine takes usually 4-5 for a usual MultiBeam work unit. So right away you would get 2x the production for (presumably) the same electricity.

If I was in your position, I might use the CPU as well as the GPU.

As far as cooling a laptop goes, what I do is take 4 water bottle caps and set the laptop on them. Put 1 cap under each corner. This provides a nice amount of space underneath the laptop. Also, don't be afraid to point a fan at the darn thing. During these summer months, I have a fan pointed directly at my GPUs in my dedicated rig.

Here's two i5 2400 rigs,

http://setiathome.berkeley.edu/show_host_detail.php?hostid=7046001

http://setiathome.berkeley.edu/show_host_detail.php?hostid=6271752

Not bad for rigs working only on CPU power.

Cheers.

I'm going to say those two systems might be overclocked a bit. They are cranking out AP work faster than my two i5-4670K's with a 400MHz high clock.

Also technically my two i5-4670K systems are running CPU only. I am using the iGPU, but it is part of the CPU.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[

Here's two i5 2400 rigs,

http://setiathome.berkeley.edu/show_host_detail.php?hostid=7046001

http://setiathome.berkeley.edu/show_host_detail.php?hostid=6271752

Not bad for rigs working only on CPU power.

Cheers.

I'm going to say those two systems might be overclocked a bit. They are cranking out AP work faster than my two i5-4670K's with a 400MHz high clock.

Also technically my two i5-4670K systems are running CPU only. I am using the iGPU, but it is part of the CPU.

Those numbers HAL, after doing some maths here, are about right as if I wasn't driving video cards, my 2500K would be doing 9-9.5K on AP's alone. ;-)

Cheers.

Here's two i5 2400 rigs,

http://setiathome.berkeley.edu/show_host_detail.php?hostid=7046001

http://setiathome.berkeley.edu/show_host_detail.php?hostid=6271752

Not bad for rigs working only on CPU power.

Cheers.

I'm going to say those two systems might be overclocked a bit. They are cranking out AP work faster than my two i5-4670K's with a 400MHz high clock.

Also technically my two i5-4670K systems are running CPU only. I am using the iGPU, but it is part of the CPU.

Those numbers HAL, after doing some maths here, are about right as if I wasn't driving video cards, my 2500K would be doing 9-9.5K on AP's alone. ;-)

Cheers.

Their tasks are running about 6.5-7 hours, at 3.1GHz?, where mine are running 7.5-8 hours at 3.4GHz. For tasks with the same blanking. So I certainly hope they are doing some overclocking, or Sandy Bridge processors are somehow much more efficient than Haswell.
I'll have to find some more systems for comparison.

EDIT:
Or I'm an idiot. Yeah. Let's go with that one.
I just remember I am running the AVX app on the CPU. It is probably why mine are running slower. The SSE version might be a better choice. Which I have not yet got to testing.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[

Here's two i5 2400 rigs,

http://setiathome.berkeley.edu/show_host_detail.php?hostid=7046001

http://setiathome.berkeley.edu/show_host_detail.php?hostid=6271752

Not bad for rigs working only on CPU power.

Cheers.

I'm going to say those two systems might be overclocked a bit. They are cranking out AP work faster than my two i5-4670K's with a 400MHz high clock.

Also technically my two i5-4670K systems are running CPU only. I am using the iGPU, but it is part of the CPU.

Those numbers HAL, after doing some maths here, are about right as if I wasn't driving video cards, my 2500K would be doing 9-9.5K on AP's alone. ;-)

Cheers.

Their tasks are running about 6.5-7 hours, at 3.1GHz?, where mine are running 7.5-8 hours at 3.4GHz. For tasks with the same blanking. So I certainly hope they are doing some overclocking, or Sandy Bridge processors are somehow much more efficient than Haswell.
I'll have to find some more systems for comparison.

Well I based my numbers here working on the average time a core on my 2500K @ 3.4GHz will do an AP in, which is 6hrs (you can check if you like), at a conservative average of 600 credits per task equals 9600 credits in 24hrs if using all 4 cores (but I'm feeding 3 GPU's)).

Also remember that a i5 2400 is very limited in its ability for overclocking.

Cheers.

Their tasks are running about 6.5-7 hours, at 3.1GHz?, where mine are running 7.5-8 hours at 3.4GHz. For tasks with the same blanking. So I certainly hope they are doing some overclocking, or Sandy Bridge processors are somehow much more efficient than Haswell.
I'll have to find some more systems for comparison.

Well I based my numbers here working on the average time a core on my 2500K @ 3.4GHz will do an AP in, which is 6hrs (you can check if you like), at a conservative average of 600 credits per task equals 9600 credits in 24hrs if using all 4 cores (but I'm feeding 3 GPU's)).

Also remember that a i5 2400 is very limited in its ability for overclocking.

Cheers.

It turns out to be operator error. See my edit on my post. I switched one of my 4670Ks over to the SSE3 app to see how that goes. Given it finally stabilized around 10K after running 5 months in its current configuration.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[

I want to also second Ianab's comment. Your CPU is pretty good. If it only takes 2.5 hours or so to complete a task, that isn't too bad. Mine takes usually 4-5 for a usual MultiBeam work unit. So right away you would get 2x the production for (presumably) the same electricity.

If I was in your position, I might use the CPU as well as the GPU.

As far as cooling a laptop goes, what I do is take 4 water bottle caps and set the laptop on them. Put 1 cap under each corner. This provides a nice amount of space underneath the laptop. Also, don't be afraid to point a fan at the darn thing. During these summer months, I have a fan pointed directly at my GPUs in my dedicated rig.

Well my CPU is Intel Core i7 4800QM (2,7-3,7 GHz) se it is almost best CPU in mobile sector (there is two more). I have more computing power than older destkop PCs based on Sandy Bridge and Ivy bridge.
So yes.. CPU is not bad. But GPU also not. I am in testing but for now it seems for sure CPU task takes about 2 or 2,5 hours for one task. Not bad. Sure.<br>

So.. GPU and CPU..oh dear;)

And cooling - my laptop is on cooling pad. but this is not the main issue. You know.. if you have 47 W of TDP in 14" laptop.. ;)

I have opened my virtual linux machine on this laptop and one task (181558 GFLOPs) takes a 2 hours and 16 minutes. Not always on max compute power.

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is there any reason still crunch on CPUs?

One reason I have found is that some projects do not HAVE any gpu capabilities. I let them have the cpu time, and SETI gets the gpu time.

On my laptops, I only run those cpu-only projects (because the gpu creates too much heat all by itself crunching), and I use a limiter to be sure the laptop doesn't get too hot. This lets them crunch harder when it is cool (over night, rainy day, ...), but throttle back when it is mid-afternoon, 98 in the shade, and no airconditioning.

I can imagine that computing in your country (according to climate) could be a challange;) For sure.. if it's rainy..all systems running temp low. Last time .. here..was about 38 °C of air temperature.. so you can imagine..that heat up even me.. not only my laptop:D

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Perhaps it is not bad to show you computer specs:
http://www.anocom.cz/adam/alien.jpg<br>

I am really thinking about experiment suggested - one month running CPU tasks. One month GPU task and see what this brings.

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