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Old 2020-01-18, 18:07   #1
storm5510
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Default Prime95 on a laptop.

I was told several months ago that running Prime95 on a laptop is not a proper things to do. The cited reasons were too much heat and a reduction in overall service life.

My laptop is an older Dell, around six years old, if I had to guess. The CPU is an i5-M220 dual core. The only work I ran on it was ECM for first factors. I left the RAM settings at the default. It is running Windows 7 Pro x64. I used the power options to reduce the processor utilization to 85%. This reduced the heat significantly. Heat-pipe tech is not the greatest.

So, I am looking for second opinion(s)...

Thank you.
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Old 2020-01-18, 18:22   #2
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Quote:
Originally Posted by storm5510 View Post
I was told several months ago that running Prime95 on a laptop is not a proper things to do. The cited reasons were too much heat and a reduction in overall service life.

My laptop is an older Dell, around six years old, if I had to guess. The CPU is an i5-M220 dual core. The only work I ran on it was ECM for first factors. I left the RAM settings at the default. It is running Windows 7 Pro x64. I used the power options to reduce the processor utilization to 85%. This reduced the heat significantly. Heat-pipe tech is not the greatest.

So, I am looking for second opinion(s)...

Thank you.
My impression is manage temperatures and it won't make much difference. We call them laptop, but they must have air flow to the underside unobstructed. They also rely for part of their cooling on the keyboard being exposed. Do not close the lid. I used to have a cat that would stroll across the keyboards or perhaps even lie on the heated keyboard. Angling the display to get in her way, or blocking up the front edge of the clamshell stopped that.

This 10 year old laptop with broken hinges from too many dives off the arm of the sofa that I still use as my main computer has run prime95 almost constantly (24 x 365 x 10) from the week I bought it. It's now throttled at about 20% on one core. I used to be able to do 45% on both cores. Before that there was no throttling needed. It seems to have a poor thermal management design and be declining in power dissipation capability with time. Sometimes it runs nicely at 60C, other times it hits the Windows thermal shutdown limit or the BIOS sudden shutdown 90C limit. A few F ambient or unexpected system background task workload variation or too much video activity seems to make all the difference. It's on its 4th? power adapter, still the first battery. They're great; a built in UPS that will keep prime95 going through most power outages. Wear level 19% after 10 years doesn't seem too bad.

Another laptop (i5-7500U) is at least 2 years old and has run prime95 plus IGP mfakto; no problems there yet except the fan assembly failed at just under a year, so earned a round trip to the Dell Texas warranty repair depot.

Third laptop i7-8750H (FMA3 capable) 6-core, doing well after a year of prime95 plus both its GTX1050Ti and UHD630 igp 24x365. This one has a hefty 120W adapter that gets pretty warm. Just maxed out the warranty extension on this one.

I had some older, 32-bit laptops I'd gotten cheap surplus running prime95 too, and of 5, 1 failed before I determined they were too power inefficient to be worth running even as space heaters. I wore out several power adapters on those.

I've given up buying the cheap allegedly designed-for-laptop model replacement power adapters. Purchase records indicate lifetime under a year for the replacements. Main laptop is now running via a universal adapter (multiple settable voltages, multiple tip adapters in the kit) that had been feeding a 32-bit laptop previously.

I have also seen old desktops and tower workstations decline in capability over time (years), going from multiple gpu plus prime95 to fewer gpus to just prime95 to failure to boot. Not sure if that's power supply aging or what. In one case a gpu developed a short that scorched a part of the ckt board and a couple of SMDs and surface traces. The HP Z600 tower would no longer start until the damaged gpu was removed. It went from happily running prime95 on all 12 cpu cores plus 3 different gpus at full load, to no longer being able to support even a lower power replacement 3rd gpu as an apparent result. Maybe the gpu failure also dinged a pcie channel or the power supply was injured.

I have "twin" Dell Optiplex 755 Core 2 Duo tower systems. Both used to run dual Quadro 2000 gpus also. Turned them off for summer. This winter when I reactivated them, one ran gpus fine again, the other refused (wouldn't boot with two or one installed; only gpu-free.) No idea why the change or the difference. They were stored in the same room.

Last fiddled with by kriesel on 2020-01-18 at 18:50
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Old 2020-01-18, 19:37   #3
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When I ran LLR on a (gaming) laptop, I also set max CPU to 85 or 90%, which bumped max CPU wattage down something like 20% (I looked up the power settings online, that number isn't from my machine itself). This kept temps within reason and prevented the fan from running full speed.

If you have one of those laptop pads that aims a fan at the bottom of the machine, temps will be pretty well controlled and you should be safe. Just make sure the exterior fan isn't aimed at the laptop fan exhaust!
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Old 2020-01-18, 19:57   #4
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Re. throttling, laptop fans are notorious for failing quickly under heavy load and gathering dust, and modern glued-together laptop designs can make it difficult or impossible to replace the fan. So keeping it reasonably dust-free by blowing air through the exhaust system every few months is a must. problem is, a typical laptop will have vents along multiple sides of the machine - my macbook has them all along the 'spine' - so it's difficult to really blow out the system, try blowing in at one point, the air just leaks out through the adjacent vent holes. Once you've identified which are 'in' vents and which the 'out', I suppose covering all but a small section of the 'ins' with a strip of painter's tape might work, and - make sure you're spit-free here - using one's own mouth might work better than a compressed-air nozzle, since one can cover the inch or so of left-open 'in' vents nicely. That's the trick I've been using on my little 5-year-old Intel NUC, which runs LL-tests 24/7 ... the in-vents there are all on one side of the case and only extend about 2 inches in width, perfect to cover with one's mouth and blow. Heard the interior fan start to whine just a couple days ago, shut unit down, blew, big clouds of dust came shooting out the 'out' vents on either side of the unit, at right angles to the 'in' side. Powered back up, been crunching silently again since.
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Old 2020-01-19, 01:14   #5
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Thank you all for your replies.

Quote:
Originally Posted by kriesel View Post
My impression is manage temperatures and it won't make much difference. We call them laptop, but they must have air flow to the underside unobstructed. They also rely for part of their cooling on the keyboard being exposed. Do not close the lid. I used to have a cat that would stroll across the keyboards or perhaps even lie on the heated keyboard. Angling the display to get in her way, or blocking up the front edge of the clamshell stopped that...
I tilt the display forward just far enough to turn the screen off. This leaves about an inch gap in the front. I also have a cat issue. 15 pounds worth. Him stepping or laying on the keyboard is something I want to avoid entirely. If something moves when he tries to step on it, no deal.

I have a widget which sits in the upper-right corner of the screen that displays the CPU core temperatures. Mid 60's on the C scale is typical with small ECM's

Quote:
Originally Posted by ewmayer
Re. throttling, laptop fans are notorious for failing quickly under heavy load and gathering dust, and modern glued-together laptop designs can make it difficult or impossible to replace the fan....
I only throttle the CPU. The fan is allowed to adjust itself as needed. The air intake is on the bottom. I can see the fan motor through the slots. The exhaust is on the left edge area. I managed to get some dust out. I am not sure if I would want to hit the intake with canned-air. If it did, it would be lightly. There is not an obvious way to keep the fan from spinning. Too fast, and it might be damaged.

Quote:
Originally Posted by VBCurtis
If you have one of those laptop pads that aims a fan at the bottom of the machine, temps will be pretty well controlled and you should be safe. Just make sure the exterior fan isn't aimed at the laptop fan exhaust!
I have a USB powered fan. Since the ports are on the right side, it would not be of much assistance. The fan blades have no guard. With the cat around, I do not run this fan unattended.
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Old 2020-01-19, 02:43   #6
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Correction: i5-M520 Arrandale.

I restarted it running Prime95. The core temperature is ranging from 61 to 73 C as the fan cycles up and down. As long as it stays this way, I do not think I will have a problem with it.
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Old 2020-01-19, 03:05   #7
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Re. cat-on-keyboard concerns - back when I still used to run my macbook on GIMPS work, when I wasn;t using it I would leave it open perhaps 6" and place it with the two thus-separated front edges down on the tabke surface, i.e. ass end pointing toward ceiling - since fan-system is forced air it really shouldn't matter which way the vents face, as long as they are not blocked by anything, but this position has the multiple advantages of keeping dust from settling on the keyboard and screen, allowing room air around all parts of the laptop, and putting the keyboard in a position where it no longer is tempting to the kitties. Only danger might be if kitty decides it likes the look of this snug warm A-frame you've built for it and crawls inside the space. Even that would probably be OK, though, unless kitty happens to body-press some bad key combos on the side wall that is the keyboard. :)
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Old 2020-01-19, 14:03   #8
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Quote:
Originally Posted by ewmayer View Post
Re. cat-on-keyboard concerns - back when I still used to run my macbook on GIMPS work, when I wasn;t using it I would leave it open perhaps 6" and place it with the two thus-separated front edges down on the tabke surface, i.e. ass end pointing toward ceiling - since fan-system is forced air it really shouldn't matter which way the vents face, as long as they are not blocked by anything, but this position has the multiple advantages of keeping dust from settling on the keyboard and screen, allowing room air around all parts of the laptop, and putting the keyboard in a position where it no longer is tempting to the kitties. Only danger might be if kitty decides it likes the look of this snug warm A-frame you've built for it and crawls inside the space. Even that would probably be OK, though, unless kitty happens to body-press some bad key combos on the side wall that is the keyboard. :)
Cats are great. I have been around them for as far back as I can remember. Provide them food, water, and a litter box, they are happy. Mine has three preferred sleeping spots. I adopted him as a kitten in 2009, so he is up there in cat-years.

I keep my laptop on a small kitchen table which belonged to my dad until he passed away in 2011. It has a polished surface so I would have to use a towel to stand it up like yours. I would need to keep it open a bit more which would keep the screen on. I have it set to turn off after 30 minutes. The cat rarely inspects the table top. Where I live is very dusty. It amazes me what the two desktops I have can collect inside in just a month.
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Old 2020-01-19, 14:19   #9
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Quote:
Originally Posted by ewmayer View Post
Re. throttling, laptop fans are notorious for failing quickly under heavy load and gathering dust, and modern glued-together laptop designs can make it difficult or impossible to replace the fan. So keeping it reasonably dust-free by blowing air through the exhaust system every few months is a must.
Thanks for posting that. A variant trial on my main laptop seems to have gone well.

Before: Ten-year-old laptop BIOS temp limit and instant halt hit again while watching https://www.youtube.com/watch?v=nOEmeyBie6g within Opera
(and Prime95 was set to stop while Opera is running)

So while it was down, I dumped a pancake compressor tank through the blowoff gun that came with the air hose kit, and laptop intake grille openings.
(No taping done, no disassembly; blasted through every intake area, sequentially working toward the exit grille, and repeat.)
The part of the bottom grille nearest the left side exit grille produced a small cloud of dust. (About a liter of dusty air.)
That area I believe is where the cpu chip, heat sink, and fan are.
(Do not try this with a freshly filled tank, or electrically connected compressor, as it may put compressor oil or condensate in the laptop. My tank had sat holding full pressure for weeks, and the compressor was unplugged.)

After: running ~10-15C cooler than the recent usual for the heavily throttled state and usual other apps, system background, etc. Then I doubled throttle percentage a couple times and then went to 100, and still running cooler than usual.
Played the video entirely, without issue. I tried it running like that a while and then tried going back to both cores, which was ok overnight (dual-core plus HT enabled TF test). Max core temps since boot 14.4 hours ago, 80C and 76C. Room ambient is a bit low currently (~4F outside last night) so not a complete test yet, but very encouraging.
Apparently that thin layer of dust has a lot of R value.
(Oh yeah, now I remember, some of the best cryogenic insulation systems are based on fine powder.)

Please remind me to do it again in 5 years. Although I'm sure the hardware will hint at it in its own way.
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Old 2020-01-31, 17:16   #10
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I put one of these under it which made quite a difference. It draws its power from a USB port. I did not connected it this way. I used a left-over smart-phone charger.
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Old 2020-02-29, 21:39   #11
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Not laptop-specific, but on the "best way to keep you kit dust-free" theme - having recently upgraded my aging quad-core ATX-case Haswell system with a shiny new Radeon VII GPU, I need to be diligent about cooling. Leaving the side panel of the case by which one accesses the guts of the system off is one part of that, but all those high-volume fans on the CPU, GPU and the PS draw a lot of air, and thus a fair bit of dust, into the system. So those wimpy compressed-gas cans sold in the computer stores aren't going to cut it, and they represent a lot of wasteful packaging, to boot. What's really needed is something akin to the dry-compressed air lines most mechanical shops have. So for ~$75 I bought a refurbished standard 2.5gal water fire extinguisher on eBay, the kind with a pressurization valve of the same kind (Schrader valve) as on car tires. Used my little car-tire inflater to dry-pressurize it, works brilliantly.

Last fiddled with by ewmayer on 2020-02-29 at 21:39
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