I have some questions about computers I was hoping to get some help with...

While running BOINC at 100%, the Task Manager shows the computer only using about 2GB of RAM. So, it seems like getting an extra 4 to 12 GB of RAM wouldn't increase the RAC of the machine. Correct? Would installing a aftermarket GPU require additional RAM from the PC to handle the extra processing power?

The Dell OptiPlex 990 SFF I'm using only has room for an Express PCI GPU. What's the best model for SETI that's small enough to fix in the box and not require changing out the power supply? If I get a low-end GPU, what kind of performance increase could I expect?

What is the maximum temperature for continuous operation. I was running my PCs wide open and was getting 52C on an older PC and as high as 70C on an I7 PC. I tried TThrottle, but it only displays temperature and won't actually regulate. I also can't open it post installation. Seems to be a compatibility issue. I have since adjusted the processing percentage down to 80% and that cooled the PCs down slightly. Can a PC be run at 100% indefinitely? What's the maximum CPU temperature for 100% continuous duty operation?

Thanks,
Patrick

The amount of RAM required to run SETI is actually quite small when only running the "stock" CPU application under 32-bit Windows XP, two GB is enough, and the operating system limits you to 3GB. With 64-bit version of Windows it is worth having more memory, up to about 1GB per thread, also if you are running the "optimised" GPU applications (e.g. "Lunatics") or SoG you might find that the 1GB/thread suggestion makes quite a difference over 0.5GB/thread.

52C sounds "ideal", while 75C sounds a "bit high" - I've no experience of Tthrottle so can't comment on how to use it, but I know a lot of folks do with varying degrees of success.

As for what low end GPU is best - I'm a high end user, so probably not the best person to give you an answer, but I would suggest you looked at something like a GTX750 which has a remarkable reputation, it is (fairly) cheap to buy, has a low power demand, and returns a RAC well above what one might reasonably expect - the only draw back I can think of in your situation is it might not fit into your motherboard so you might need to consider a header or adaptor to "jump the gap".

(The small format Dell cases are a real pain when it comes to getting the heat out that any GPU produces, so be careful when considering installing any GPU, also Dell have a reputation for cutting the PSU right down to the bottom line.)

With popper cooling PCs will run for a long time, a very long time - mine all run at "manufacturers intended", and are on 24/7, and one has been running like that for a couple of years - the biggest issue I find is that many of the cooling fans are not designed for that duty cycle, I've got several GPUs which have bee dragged to their death by very inadequately engineered cooling fans :-(

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

While running BOINC at 100%, the Task Manager shows the computer only using about 2GB of RAM. So, it seems like getting an extra 4 to 12 GB of RAM wouldn't increase the RAC of the machine. Correct?

More RAM will not help your RAC on SETI.

Would installing a aftermarket GPU require additional RAM from the PC to handle the extra processing power?

Check the requirements of the video card you plan to buy. In general, they shouldn't require extra RAM in most modern computers.

The Dell OptiPlex 990 SFF I'm using only has room for an Express PCI GPU.

PCI Express has different connectors, the shortest being an x1 connector, followed by an x4, an x8, and an x16. To make matters more confusing, an x16 connector can electrically be any of the other specs (x8 on down), but the reverse is not true. Video cards are all PCI Express x16 connectors.

So, before we can answer your next question, you need to verify what type of PCI Express connector you have in your Dell SFF computer.

What's the best model for SETI that's small enough to fix in the box and not require changing out the power supply? If I get a low-end GPU, what kind of performance increase could I expect?

Currently, the most energy efficient GPUs that do not require purchasing high end power supplies are anything using the NVIDIA GTX 750ti or 950ti graphics chips. These are considered "low end" (but far better than onboard video). I don't have hard numbers but these cards should be able to get around 10-15k RAC using the stock app alone.

What is the maximum temperature for continuous operation.

That's going to depend greatly on the specific components you have and their thermal thresholds. Obviously the cooler you can keep them, the better.

Can a PC be run at 100% indefinitely?

Yes, assuming proper care and cooling requirements are met. Note most mobile devices do not meet the proper cooling requirements to run 100% indefinitely.

What's the maximum CPU temperature for 100% continuous duty operation?

That's too ambiguous of a question. The answer is going to depend on the specific CPU used.

Lots of good info...

Thanks Guys!

Seeing as you have an SFF case then checkout Gigabyte's and MSi's low profile GTX 1050/Ti cards. ;-)

Cheers.

The i7 4770k was reaching 90+ degrees when running 100% using the intel CPU fan, so 70's might be considered as acceptable. I had to install liquid cooling for the CPU to control the temps.

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You have quite a range of computers on your list to say what is best for each with completely different processors/mem/OS, and have no idea if they are used for anything else than crunching tasks on seti.

For performance, I would recommend Ubuntu 14.04 it is quite impressive how it runs on my AMD4200+ with a 750Ti and only 1GB or ram - good for your 2GB CoreDuo's. And on my i7 it uses just over 1GB, wow.

For video cards, as said GTX-750, 950, 1050 series are on the low end and all perform well with little power use. A 450-500W power supply should work with most single card setups, even for high end cards, as long as that is all you need power for, not a pile of hard drives. My 980+1070 i7-3820 is drawing about 400W @ full throttle for comparison. Most cards use a 6 or 8 pin external power cable, but adaptors can be had to convert from molex or sata power cables.

Moving up to the 60, 70 and 80 series will see almost a doubling of RAC each set up, with the 10xx generally being the lowest power use. The 750TI=I has become well known for it's performance/Watt rating.

All cards are 2x slots, meaning they take 2 external slots for each PCIe slot. PCIe x16 is required for all cards, but with the use of adaptors can work in PCIe x1 slots. You might find a single slot 1050 - not sure if they are out yet. As you go up in series the card length get longer, so watch your space available to card length.

Cooling is always an issue, TThrottle should have worked for you. Generally 70C is OK, but it depends on your CPU, you have to look at the specs for each. My i7-3820 is rated at 66C and i5-4460 72C. Video cards can generally be pushed into the 80s but low 70C range is much better. PercisionX is another great program for maintaining GPU (not CPU) temps through fan control and temperature throttling.

My i5 with a 750Ti is about 23,000 RAC, so yes, a small card can produce good results.

PCs can run a long time at full power if you keep them cool, as said fans do give out, and monthly cleaning is a good idea.
Dust = Heat = DEAD!

Cases also help a lot with heat. A cheap full height ATX case can be had for $60 with 120 or 140mm fans included. Worth considering moving components into a new box with good airflow. Or as others have done (it you don't care about looks) go case-less :)

That's all for now, My 2 cents (1.5 in USA) LOL

Here is a SFF system that has a low profile MSi GTX 1050 Ti in it, https://setiathome.berkeley.edu/show_host_detail.php?hostid=7972413.

Cheers.

You will need a low profile gpu card.

To my limited knowledge, GTX 750/950 does not exist in low profile size.

There are GT 740 that were made in regular and low profile sizes. I would make GT 740 the lowest acceptable option, and even then it is waste of money.


As far as system ram. The main reason to have as much ram as the chipset will support is so that you can run multiple applications. BOINC does not force you to buy and install maximum amount of ram. If all you run is a few programs at a time and BOINC is one of them, then don't bother adding ram. On the other hand, now that DDR3 is going out of fashion and production, if you can max out the ram for cheap, then do it. Once DDR3 ram is not used in new pc, it will disappear off the market and spending top dollar for used ram when you know you will replace the whole pc in a year or so is also waste of money.

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Here is a SFF system that has a low profile MSi GTX 1050 Ti in it, https://setiathome.berkeley.edu/show_host_detail.php?hostid=7972413.

Cheers.

I agree with wiggo.. Those optiplex are finicky. Not a lot of space. As as far as upgrading the power, don't bother. You should have enough in the stock psu to power that MSI. Also, sometimes those optiplex don't like other PSU, so might be more hassle than it's worth. Best bet, go with the MSI

My 2 Cents..

Zalster

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After reading all the comments, I decided to go with a GTX1050ti. While it will fit in the larger DUO PC box, it's still too big for the SFF PCs. The box on the SFF is only 4 inches wide and I couldn't find any video cards that would fit those dimensions.

I just recently got back into this and didn't know that GPUs could be used for SETI. Had I known, I would have gotten PCs with bigger boxes. I looked at the ATX box and I like the idea of moving out of the SFF boxes to make room for video cards. I'm concerned about the comments that Dell's don't like other power supplies. I also couldn't find higher wattage Dell PSs on Amazon, 250-300 Watts seems to be max. If I'm moving to the bigger box, I want to upgrade the power too. Anyway, I'll see how it goes with this first upgrade and may look at the ATX upgrade for a future project.

After reading all the comments, I decided to go with a GTX1050ti. While it will fit in the larger DUO PC box, it's still too big for the SFF PCs. The box on the SFF is only 4 inches wide and I couldn't find any video cards that would fit those dimensions.

I just recently got back into this and didn't know that GPUs could be used for SETI. Had I known, I would have gotten PCs with bigger boxes. I looked at the ATX box and I like the idea of moving out of the SFF boxes to make room for video cards. I'm concerned about the comments that Dell's don't like other power supplies. I also couldn't find higher wattage Dell PSs on Amazon, 250-300 Watts seems to be max. If I'm moving to the bigger box, I want to upgrade the power too. Anyway, I'll see how it goes with this first upgrade and may look at the ATX upgrade for a future project.

Those cards come with 2 different back plates to suit both types of cases, you just have to put the right 1 on. ;-)

Cheers.

After reading all the comments, I decided to go with a GTX1050ti. While it will fit in the larger DUO PC box, it's still too big for the SFF PCs. The box on the SFF is only 4 inches wide and I couldn't find any video cards that would fit those dimensions.
.........

Maybe ATI mat be the way to go it that small box. I have an ATI R7-240 that is really small and would easily fit. It certainly is no screamer with the performance equal to 1 Intel i7 core, but it would fit with no external power needed. I'm not sure how many series you could go up on these low end cards and still fit, worth looking into.

no external power needed. I'm not sure how many series you could go up on these low end cards and still fit, worth looking into.

GTX 1050Tis are now available in low profile.

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Grant
Darwin NT

Nice there Grant, and no external power needed for that 1050Ti.