I'm more of a fan of the SSD route because I like fast boot times. I have a couple of SSDs in my work machine that I'm trying to break but with no success. The boot drive is a Samsung 840 Pro that used to be in a virtual server environment. 20,000 hours of work time and 10TB of writes. 99% health and 9 years of life left. The secondary drive I use for writing disk images so that's 6,820 hours of work time, 14TB of writes, 100% health and 8 years of life left. I have 32GB of RAM and yes a RAM-disk would be faster but since disk I/O is not a bottleneck, a RAM-disk wouldn't improve RAC.

295x2 has two fans; one small fan in the card runs at higher speed and a larger fan on the radiator. We got some APs last night so for comparison my 290x runs at 86C but the 295x2 runs at only 68C.

I don't know that you can directly compare cpu and gpu water cooling, but for now I'm running a Corsair H100i with low-rpm Noctua fans on an 88W 4790K cpu underclocked to 3.49GHz. At 5% average CPU utilization the cpu temp is 48C.

EK-KIT D360-X2 (CaseLabs Mercury S8 drop-in) is $515.83. EK-FC7990 - Acetal+Nickel incl. Backplate is on sale for $112.09 but you could be looking at up to four of these. I'm sure there are other costs involved.

A long time ago I bought a dual-cpu server from a friend and I remember that thing ran hot. So obviously dual-cpu means dual-fans and double heat, but the I assume you want to get that heat out of the case. So the solution is to double the airflow but that will probably quadruple the noise. So one of my Noctua fans might be 22dBA but a Vantec Tornado is 55dBA. Inside a server room noise isn't a problem and every time you turn your computer you feel like you're achieving maximum warp, but that gets old after a while, unless you're deaf already.

So one thing you could is just run the cards like normal. Hopefully the backplates don't block too much airflow and cards 1-3 don't get too hot.

You could also use risers to put a gap between the cards; you need to be creative if to secure everything down. I was just about to use risers myself but I just noticed that my reference 295x2 is shorter in height than my non-reference 290xs. So if I sandwich the 295x2 in between two 290xs, the first 290x might be able to breathe over the top of the 295x2.

Or you could just build two computers with two cards each and there would be enough space between the cards so that they wouldn't overheat. I'm sure the 2000W superflower isn't cheap, and getting one to work without popping breakers and blowing fuses could be a challenge.

Boot times are for me not so relevant. :-)
The PC will work continuously 24/7 - I guess every 2 weeks I make a reboot just for to empty/refresh the system-RAM and VRAM of the GPU cards.

I think also to the times if SETI have no new tasks ready for download.
So the PC will ask at Einstein or Milkyway (or other projects) for new tasks - I guess.
AFAIK, Milkyway is very good for ATI/AMD GPUs. Just 'a few seconds' (on ATI/AMD GPUs) and the projects tasks are finished.
But they have a barely measurable 'tasks in progress' policy - IIRC - like max ~40 tasks in progress/PC. This means every 60 second project update for to feed the Monster. ;-)
IIRC, BOINC download a big file at Milkyway (have no idea how big it was but it lasts very long to download ;-) 4MB or 40MB for to start to crunch a few tasks.
Then the following tasks are very small, because they work with the before downloaded big file.
After this, again a big file is needed to download.
So I thought a HDD would be better than SSD. (write, write and write ... ;-)
We will see. :-)

It looks like currently I can't buy the EK-KIT D360-X2 in Germany (listed since 23. April 2015).
It looks like EK-FC7990 is out of stock in Germany (listed since 16. May 2013).
But nevertheless thanks.

I looked to the fuse box, the room which I will place the Monster is fused together with an other room (one 16A fuse).
In both rooms just 40W bulbs are switched on sometimes.
The 230V/16A/3680W wall plug, can be used up to 3600W. :-)

Hints and tips are very welcome.

Thanks.

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Boot times don't affect RAC, but it's all about what you're accustomed to. I have a computer that boots off an SSD in less than a minute. My boss asks me if I have any cheap SSDs laying around so I give him the SSD so now I put in an old hybrid drive and that takes several minutes to boot. I might only reboot once every couple of weeks, but if something takes several minutes to boot I always wonder if it locked up.

I haven't spent any time on Milkyway but if it writes more than 1TB/month(which I doubt) and you don't trust SSDs(the technology hasn't been around for a century) then maybe bare metal is the way to go. I tried Einstein for a bit but I was only processing the huge tasks that could take an hour or more to complete. Yes there were large downloads and some writes but I didn't fear for the health of my hard drive. My computer would download maybe 10 tasks or so which might be about half a day's worth and it would only need to check in once every 2-3 hours for new tasks.

I posted the information on water cooling not with the expectation that you would make a purchase decision, but more to just illustrate the costs involved. EK is not the only company that makes water cooling kits and they're not the only company that makes 7990 waterblocks/backplates either.

I had a problem where I was running 5 gpus off one surge protector and my systems would shut off. So now I just have 3 gpus on that surge protector and the other 2 gpus are on another outlet.

I'm an 'old' man and don't trust new technology. ;-)

A SSD would work well in this combi, I guess, but at night I will not get sleep, because always I'll think, the SSD will survive ...?
And what will happen with me if I don't get well sleep over years ...? ;-)

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I'll soon enough get some SSD's, but from a raw install I only know to set the bios/firmware to ahci, how do I load the driver? Probably from a USB drive or a CD/DVD disc. For PCs that just crunch, I'll limit the size to 128GB Samsung 850 Pro drives, and a 1TB Samsung 850 Pro for My PC, kind of like what I had to do on the 3rd party bios chip that used to exist, called 'MR Bios'..

Sorry it's just a Google search for the term.

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The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

1TB WD VelociRaptor 64MB 3.5" SATA 6Gb/s - WD1000DHTZ (2.5" HDD in a 3.5" 'heatsink')

Like I wrote I'll go with the above mentioned HDD.

It's 1TB (1000GB) HDD, but later it will be just 932GB für usage.
AFAIK, this drive have 3 disks inside.

How to speed up this HDD?

I make three partitions (C, D, E) each disk one virtually HDD (each with 310.6666666666667GB).
Windows to C.
BOINC files folder to D.
BOINC data folder to E.

(Each disk inside the HDD have his own read/write heads.)

This would speed up something? (e.g. shorten access times)

Thanks.

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Partitions 'divide' the drive by cylinder - not by platter
http://www.snia.org/education/storage_networking_primer/stor_devices/data_structure

C: will be on the outer rim = will be fastest (so it's good to have the OS on C:)

I don't think you can feel/measure any difference in the speed of BOINC/apps from the speed of HDD, maybe even 10 years old 80 GB HDD will have enough speed for BOINC
Any difference will be < 1%

(Each disk inside the HDD have his own read/write heads.)

If the HDD have 6 read/write heads they all move together.
From the link above: "The multiple arms of a drive move together in lockstep, positioning the heads in the same relative location on all platters simultaneously"

http://en.wikipedia.org/wiki/Disk_read-and-write_head

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- ALF - "Find out what you don't do well ..... then don't do it!" :)
 

1TB WD VelociRaptor 64MB 3.5" SATA 6Gb/s - WD1000DHTZ (2.5" HDD in a 3.5" 'heatsink')

Like I wrote I'll go with the above mentioned HDD.

It's 1TB (1000GB) HDD, but later it will be just 932GB für usage.
AFAIK, this drive have 3 disks inside.

How to speed up this HDD?

I make three partitions (C, D, E) each disk one virtually HDD (each with 310.6666666666667GB).
Windows to C.
BOINC files folder to D.
BOINC data folder to E.

(Each disk inside the HDD have his own read/write heads.)

This would speed up something? (e.g. shorten access times)

Thanks.

with 3 HDD, you can make RAID5...that will give you about 33% more speed, with securitxy for your data...
with 2000GB of DATA on 3disks...

if you put 4th disk, you can go on RAID10...and have 50% of the speed over single drive! ;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

No. ;-)

I guess I took the wrong 'disk' instead of 'platter'?

It's just one real HDD, inside of this device are 3 platter (in my case).

I just wanted to make from one real HDD (C) three theoretically HDDs (C, D, E (partitions)).

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This SSD endurance test finally finished last month and they have some data on SSDs. The sample size is TINY and should be put into proper perspective but the results are interesting. I have my new Intel SSD 750 1.2TB PCIe drive sitting next to my machine and I am working up the courage to replace the existing rotating drive.

The SSD Endurance Experiment: They're all dead
This is the end, beautiful friend
by Geoff Gasior — 10:22 AM on March 12, 2015
http://techreport.com/review/27909/the-ssd-endurance-experiment-theyre-all-dead


The SSD BIOS manages error detection/correction and wear algorithms to keep the SSD healthy. Like HDDs, the BIOS retains spare good blocks to remap on read error detection and warn of impending failures. NOTHING beats a regular backup though.

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AFAIK, BOINC can manage up to 8 GPU chips.

(So 4 (dual GPU) AMD HD7990 VGA cards are OK.)

8 GPU chips is the max?

(I could add 3 NVidia GPUs (low profile (1 slot wide) VGA cards), if I use PCIe riser for 4 slots, 3 slots are unused. And CreditNew isn't screwed up if I use (NVidia (other manufacturer)) VGA cards with other performance.)

[EDIT: E.g. 2048MB KFA² GeForce GTX 750 Ti Razor - 75IPH8HXB9XX (max 60W usage)]

But then this would mean BOINC must manage 11 GPU chips - is this possible?

Thanks.

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AFAIK, BOINC can manage up to 8 GPU chips.

(So 4 (dual GPU) AMD HD7990 VGA cards are OK.)

8 GPU chips is the max?

(I could add 3 NVidia GPUs (low profile (1 slot wide) VGA cards), if I use PCIe riser for 4 slots, 3 slots are unused. And CreditNew isn't screwed up if I use (NVidia (other manufacturer)) VGA cards with other performance.)

[EDIT: E.g. 2048MB KFA² GeForce GTX 750 Ti Razor - 75IPH8HXB9XX (max 60W usage)]

But then this would mean BOINC must manage 11 GPU chips - is this possible?

Thanks.

As I recall the BOINC client can use more, but BOINC server code would only believe there were up to 8. I think this was updated 16 at some point, or maybe there was only talk of it. There has also been mention of driver limits for the total number of GPUs as well.

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
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A few days and he's online. :-)

Now I see, that I need an adaptor.

You know this adaptor, 2* 4pin molex (male) to 6pin PCIe (male) (normally delivered with a VGA card), I need something the other way: 6pin PCIe (female) to 4pin molex (female).
I searched the web, but couldn't find.
This adaptor don't exist?

The PCIe extender riser cable have a 4pin molex (male) (that the VGA card get power - like over the PCIe slot).
The PSU have 4* 6pin PCIe (male) ununsed.
Both is for 75W, so it's OK.
But I need to connect the PCIe 6pin (male) with the 4pin molex (male).

Thanks.

Male, female, I'm confused now...

»That's« the normal adaptor which comes with a VGA card.

I need something like »this«, but on both end the contrary.
A 6pin socket like at a VGA card and at the other end a 4pin molex like at a cable from the PSU (at the 4pin molex just the yellow and black cable/pins are connected, each with 2 cables).

EDIT:
»That's« the PCIe extender riser cable.

OK, I ordered the following: »2*4pin« and »6pin«.

...and will make my own adaptor.

I take the 6pin and cut of the 8pin,
I take the 2*4pin and cut of the one 4 pin.

On one side 6pin on the other side 4pin.
I connect all 3 black and all 3 yellow to one cable each of the 6pin and connect them each to black and yellow to the 4pin.

This will work, or this will destroy my whole hardware?

Thanks.

EDIT: Someone know because of the 4pin connector of the PCIe extender riser cable, why there the yellow but not the next black but the after next black is connected?

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You don't have any spare 4 pin or SATA power connects from your PSU?
I could see maybe no 4 pin connectors, but you could always use a SATA to 4 pin adapter.

EDIT: Also if making your own cable. On 6-pin PCIe power connector. The middle black wire is designated as "sense" rather than ground. So it may not be advisable to use as "ground" connection.

On connector gender. You are looking for PCIe male to 4 pin female. May people get the connectors confused. No matter which way the plastic connector goes. The connector gender is more by if there are pins pointing out... just like on humans males?

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SETI@home classic workunits: 93,865 CPU time: 863,447 hours
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The Super Flower 2000W PSU have 4 'periphery' cables, 2 with molex 4pin and 2 with SATA connectors.

1 molex 4pin cable from the PSU I connect to the EZ-Plug of the mobo (power for the PCIe slots). (They don't deliver the power, because the PCIe extender riser cable have power connector, but maybe this way or this way this EZ-Plug need to be connected for correct function of the PCIe slots)

1 molex 4pin cable from the PSU I connect 26* 120mm 1900RPM fans (if 5W each then this are 130W for this cable. (I guess it's enough, or how much wattage can survive such a cable?)

Then I have 2 cables from the PSU which have SATA power connectors.
Then I would need an adaptor which make molex 4pin from it.

If so, then every SATA power connector must deliver (survive) 75W, if I use two SATA connectors of each cable, then the whole cable must deliver (survive) 150W.
This can deliver the SATA connectors (75W) and this cable (150W)?

Not to forget the SATA HDD, which will use maybe 5W! ;-)

I need a way to connect the PCIe extender riser cables with the PSU.
Every PCIe extender riser cable need 75W, so this are 300W.

I thought a 6pin PCIe connector can deliver 75W, why not to connect him with the PCIe extender riser power connector which need up to 75W?
But this are 3 black and 3 yellow (6pin PCIe).
If I use just the left up+down or on the right up+down black and yellow cables, this two cables can deliver also 75W?

I guess if I connect/combine all the 3 yellow cables of the PCIe plug to 1 yellow cable and the left and right black cable also to 1 cable, this will not work, because this will be a 'yellow' short circuit, or not?


I need an adaptor with (if this would work):
»connector on the left« (here I connect the power connector of the PCIe extender riser cable)
and at the other end of the cable
»connector on the right« (here I connect the PCIe 6pin connector from the PSU)

But just one yellow and one black cable connected between both connectors.
But over this can go up to 75W?

Thanks.

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The Super Flower 2000W PSU have 4 'periphery' cables, 2 with molex 4pin and 2 with SATA connectors.

1 molex 4pin cable from the PSU I connect to the EZ-Plug of the mobo (power for the PCIe slots). (They don't deliver the power, because the PCIe extender riser cable have power connector, but maybe this way or this way this EZ-Plug need to be connected for correct function of the PCIe slots)

1 molex 4pin cable from the PSU I connect 26* 120mm 1900RPM fans (if 5W each then this are 130W for this cable. (I guess it's enough, or how much wattage can survive such a cable?)

Then I have 2 cables from the PSU which have SATA power connectors.
Then I would need an adaptor which make molex 4pin from it.

If so, then every SATA power connector must deliver (survive) 75W, if I use two SATA connectors of each cable, then the whole cable must deliver (survive) 150W.
This can deliver the SATA connectors (75W) and this cable (150W)?

Not to forget the SATA HDD, which will use maybe 5W! ;-)

I need a way to connect the PCIe extender riser cables with the PSU.
Every PCIe extender riser cable need 75W, so this are 300W.

I thought a 6pin PCIe connector can deliver 75W, why not to connect him with the PCIe extender riser power connector which need up to 75W?
But this are 3 black and 3 yellow (6pin PCIe).
If I use just the left up+down or on the right up+down black and yellow cables, this two cables can deliver also 75W?

I guess if I connect/combine all the 3 yellow cables of the PCIe plug to 1 yellow cable and the left and right black cable also to 1 cable, this will not work, because this will be a 'yellow' short circuit, or not?

I need an adaptor with (if this would work):
»connector on the left« (here I connect the power connector of the PCIe extender riser cable
and at the other end of the cable
»connector on the right« (here I connect the PCIe 6pin connector from the PSU)

But just one yellow and one black cable connected between both connectors.
But over this can go up to 75W?

Thanks.

OK now I see your limit on connections with the PSU.

With the 2 8-pin EPS 12V connectors I would expect enough power to be delivered to PCIe slots that you will be using directly. If MB states to use 4-pin molex also then it knows better than I, but I'm not clear why it might be needed.

The 4-pin molex connectors are rated for 13 amp, but that is the connector. The specifications for peripheral connecters generally state that no more than 5 amps per connector or 60 watt for 12v. I read that to mean a cable with 4 connectors is expect to be to deliver 20 amp. Where as a cable with 2 connectors would be expected to deliver only 10 amp.

When splicing the adapters together to make the one you need. Remember the PCIe connection is rated for 75w. So that is combination of all cables attached to the connector. Connecting all yellow together should not be a problem with a single 12v PSU. They are all connected together on the other end.
Rather than make a special adapter. You could remove molex connector from PCIe riser & connect 6-pin PCIe connector directly.

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Yes, thanks, this would be also a good idea...

»This« is the PCIe riser.

The molex 4pin connector have two yellow and two black cables just on two pins of the four pins.
I cut of the molex 4pin connector.

(why not the black at the side of the yellow cable is used, one pin between both are unused. The 2 black in the middle of a molex 4pin are not the same?)

I take »this adaptor« cut of the PCIe 8pin connector.

Then I connect one yellow + black cable from the PCIe riser to one yellow + black cable from the PCIe 6pin connector (up+down left),
then I connect one yellow + black cable from the PCIe riser to one yellow + black cable from the PCIe 6pin connector (up+down right).
Then the pins in the middle of the PCIe 6pin connector are not in use.
This means, two yellow deliver the power to the PCIe riser.
This would work and surive the 75W?

Thanks.

If I understood »this article« correct, then the left and right (yellow + black) cables of a PCIe 6pin connector can deliver 75W (just 4 pins).
I'm right?
So then the above mentioned mod should work.

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