hello,

i used the app to double the workunits per core ages ago but saw practically no differance in throughput
so i'm wondering why so many of the highest rated hosts on this project are using them ?
is it because of the multiple gpu's per machine there running that there is a benifit to running 8 work units from 4 gpu's ?
or do you get more of a bank of work units downloaded to your machine because it thinks you have 8 cores instead of 4 ?

there must be some reason i just cant fathom it
something else i cant fathom now that i've returned from an extended holiday is that there seems to be two differant types of wu with differant times to complete
now thats fairly ok but what i dont understand is the various differant times the same type of work units seem to be crunching at

thankfully i havent had the failed work unit problem some have had or not that i've noticed but i did like the work units of a same type finishing in a same amount of time as it helped in fault diagnostics etc etc

sorry about all the questions

best regards
Ian

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Running 2 WUs at once give you the following benefit: the current 0.62 app still has to do some calculations on the CPU. This takes a couple of seconds per WU, depending on CPU speed of course. During this time the GPU is idle. If you run 2 WUs in parallel chances are pretty high that the GPU can continue crunching on the 2nd WU if the 1st one gets into this CPU phase.

For my machine (overclocked HD6950 with unlocked shaders and a Core 2 Quad 2.88 GHz) running 2 WUs in parallel yields a throughput increase of ~9%. I can't do it with Catalyst 11.4 anymore, though.

Edit: there's a flexible amount of work in each MW WU. You can compare their times if you only compare WUs which give the same amount of credit.

MrS

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Scanning for our furry friends since Jan 2002

hi

thanks for your quick reply as i say i tried this a long time ago so maybe theres more of an effect now

I'm running a i7 920 at 4 gig with twin 5970's using 4 GPU's

so any increase in throughput i suppose would be even more amplified

my only problem with overclocking the 5970's is heat and lots of it ( what do you mean unlocking the shaders ? ) i though on this project fiddling with all that sort of stuff made no impact as it was sheer GPU power that was needed

i have to run them at stock and lower mem clocks just to keep the temps around 85 degrees :(

whoever designs the air intake designs on these cards needs shot because when you use two they basically sit slap bang next to each other and even sticking something in between them to seperate them as mush as possible and aiming twin 4 inch fans at the gap doesnt help much grrr

so if running two wu per core makes extra heat then i may not be allowed to do it anyway :(

best regards
Ian

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....Please Join team Scotland HERE

hi,

just made each core have 2 wu each and as expected slightly more heat running around ( maybe because of more work being done ? )

and as expected the wu have doubled in there crunching length

but i had a look at your system wu and nearly fainted how on earth are you getting work units finishing in around 60 and 90 seconds for each differant type if your running twin wu on one core ?

mine are now running at between 200 and 250 seconds each which is way slower than yours even though my cards are only modestly overclocked i'd have to overclock the thinks to 2 ghz to get anywhere near those times

so is there something i'm missing here ?

Ian

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....Please Join team Scotland HERE

...so is there something i'm missing here ?

Ian

No, he's running a 6970, which are good single core beasties. As you are running two per core, divide your time by two, then compare against his (with same size WU), and you will see the speed difference.

Your 5970 times are up to expectations for 800/500.

I suspect from 5970 history, and your comments above you hit the 5970 heat barrier on memory chips. A few things I found helps with 5970s

- Bring the memory chip bandwidth down to 300. PM me if you dont know how to in CC (it defaults to 500 in CC, thats pure software, easily goes lower)

- Use the bigger Crossfire strap. The latter allows a bigger separation on the motheboard of the cards (one or two slots depending on the motherboard), grately improving airflow. They are £2 or £3 on ebay (dont pay the outrageous £10+ asked by some - if you cant find any, PM me your address, I have a spare you can have)

- Obvious I know .... but often missed ... give the 5970 fans a heafty squirt of compressed air, including the intake/outtake grids - if the latter have not been done you are likely to be surprised at the resulted dust cloud :)

- This one is cash dependent .... but the effect is astounding. If you are not a watercooling fan, get the Arctic Accelero Extreme third party cooler. It will take off 40 degrees C from GPU temperatures, and around 15-25 degreea C off VRM temperatures. Its a second best to watercooling in terms of pure temperature loss - but the latter is mere statistics, they work extremely well. There is a trip and trap to fitting them, so PM me if you decide to do it, and I'll point you at the problem and solution of fitting. The easiest thing frankly is toss £40 at an installer who has fitted them before, job done. With those fitted, both cards in a box will resemble fridges, not cookers, and you will easily crank up the volts & o/c with no heat concerns. You will need to watch your PSU if they are cranked fully up, you will not get away with less than 1000w PSU if both cards in a box are taken to their extremes.

EDIT: sorry forgot one thing one your previous comments:

.....
so if running two wu per core makes extra heat then i may not be allowed to do it anyway :(

With the current WUs it does, much more than 0.28 did. I could run 2 x WU per core on a 5970 with 0.28, not with 0.62 though ... the GPU memory temperatures took off, even with the above coolers fitted to both cards, and longer Crossfire strap (its the effect of the 5970 design fault on the memory chip placing). Stopped doing it in the end because of that. 8 WUs running through 2x5970s was just too much with 0.62 WUs.

Regards
Zy

I'm running just 1 WU at a time due to driver problems - no need to get a heart attack yet ;)

The main difference in speed between our cards is the architecture of the chips. Your "Cypress" GPU has 1600 shaders, whereas my "Cayman" has 1536 shaders of a different architecture. They work out to be equivalent to 1920 shaders of the "old" architecture here at MW (using double precision). That means my chip can do 20% more work per clock . By unlocked shaders I just mean that my HD6950 2 GB card normally has "only" 1408 shaders (+10% compared to yours), but I was able to use the full 1536 shaders (as on a HD6970) by using a modified BIOS.

Let's compare the 2 hosts. You need about 272 s for 2 WUs of 267.2 credits. I need about 94.3 s for such a WU. Your time for 1 WU would be 272 / 2 = 136 s. If you also had 20% more shaders you'd need 136 s / 1.2 = 113.3 s. Finally I'm running at 900 MHz chip clock, whereas you're running at 800 MHz. If you could use 900 MHz you'd finish such a WU in 113.3 s * 800 MHz / 900 MHz = 100.7 s. Not sure where the additional 6% difference comes from, but you're certainly not far off here. One factors is that while running 2 WUs in parallel you have to give the setup soem time, so the 2 WUs can get "out of sync", i.e. their idle GPU time is not overlapping.

Regarding temperature: the HD5970 is a real monster and pushing the boundaries of what can be cooled using a 2 slot air cooler. Adding a 2nd one without and additional slot between them doesn't help matter, and neither does the blocked air intake help.

Running 2 WUs in parallel will increase heat, but not dramatically so. Unfortunately there's not much you could do about this. You could go for water cooling (not that I'd suggest this, I don't think it's fun to setup and maintain). Or you could try lowering your GPU voltage. Not sure if there are software tools for the HD5970 to do this. You might have to lower clock speeds for stability, but you could start by staying at 800 MHz and lowering the voltage as far as you can. This will save you electricity cost and lower temperatures.

Edit: too late :p
One more note: with an Accelero Extreme your card uses 3 Slots if I remember correctly. Make sure you've got the space between PCIe slots available.

MrS

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Scanning for our furry friends since Jan 2002

wow thanks guys loads of useful info

i'm using the Gigabyte GA-X58A-UD7 Intel X58 motherboard
http://www.overclockers.co.uk/showproduct.php?prodid=MB-229-GI&groupid=701&catid=5&subcat=1692
which when i look at it has 3 blue pcie slots together which just now have each of the cards in slot 1 and 3 the only other blue slot i can see i dont know if its a proper slot for x-fire is a slot in fifth pace the other side of a white pci slot there is a gap of some two or so inches from slot three where the second card now resides and the 4th blue slot that i take it is another pcie slot that can be used for crossfiring these two cards
that would mean the first card in the 1st blue slot and the second card in the 4th blue slot which would need a bridge of about six inces or more so i cant see that being correct
plus the 4th blue slot would squeeze the card against the bottom of the case even though it is a pretty large case or it was but not maybe compared to the monsters people use today

this is still quite an expensive motherboard so would like to think that all of these 4 blue slots can be used for full pcie16 data transfer ?

then i'd just have to get a bigger case as the second card would hang of the end of the motherboard

let me know what you think

Ian

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....Please Join team Scotland HERE

..... this is still quite an expensive motherboard so would like to think that all of these 4 blue slots can be used for full pcie16 data transfer ?

let me know what you think

Ian

That one has 4 PCI-E slots, but the breakdown is 2xPCI-E x16 & 2 x PCI-E x8. Not that really matters as such because a x8 PCI-E would eat anything we throw at it, maybe as time goes on given a 5-10 year motherboard life, it might choke a little, but you would need to be throwing some chunky kit at it to choke it.

The one I use is the MSI 890FXA-GD70 as I have a 1090T. If you look at the layout in the link, whilst in no way saying its the same - the layout is *similar*, and I have a 5970 in the top blue slot, and a 5970 in the bottom blue slot, on crossfire with the extended Crossfire strip, and an Accelero Extreme Cooler fitted to both. So from the size shown in the pic you referenced, I would have thought it would crossfire fine. It should fit 2 cards with coolers, or four cards no third party coolers. Obviously needs measuring precisely though.

If you are going that far re motherboard abilities, I would recommend getting a ASUS Rampage III Black Edition, its hard/impossible to beat in terms of X58, its one of the top - if not the top board for the X58 chip. ASUS released it April, same price range as the one you referenced, and feature set is higher. GURU3D raved about it - worth reading that review in full. Need to ferret a little re size/case size (almost certainly need tower case), and slot clearance re cards/third party coolers/no third party coolers.

....then i'd just have to get a bigger case as the second card would hang of the end of the motherboard ....

With 5970s that will happen with any motherboard. The size issue is - is there enough room from the end of the 5970 cards to the back of the drive cages inside the Case? You need to allow 2 or 3 inches of room to cater for the cable bunching and turning "a corner" as you put it together - as well as clear work room space for future fiddling around. For 5970s - whilst not absolute - it pretty well means a tower case for two of them, if there is to be quality cooling. A mid tower is feasible, I squeezed two in one - but didnt take long to penetrate my skull that that was a baaad idea :) Got a Full Tower, and all is well now.



Regards
Zy

hi,

thanks but the board your using appears to have way more space between the first 4 blue slots so that i think youd at least have some gap if you put one card in slot 1 and the other in slot 4 youd have a rather nice gap without running out of motherboard lol

the motherboard you mention looks great unfortunately i pretty much only ever upgrade motherboards if they break or some new cpu chip config comes out making the board usless

i was thinking of somehow attatching a cpu cooler somehow to the metal backplate of the first card see if that has any effect on cooling the heatsink
not sure how i'm going to do that yet though

by the way i take it the red openings at the end are intake holes as i was thinking of sticking a fan pointing directly into them too lol

Ian

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....Please Join team Scotland HERE

Yeah, Zydors board is much easier for cooling. The problem with yours is that the 16x PCIe slots only start from the 3rd slots (counting from the CPU), that's why it gets so cramped. You might try one of your cards in the uppermost and the other one in ther lowest slots, though. Never mind the 8x connection for crunching.

BTW are you using 4-GPU X-Fire for gaming? For crunching you shouldn't need X-Fire at all.

And I certainly wouldn't go from a high end X58 motherboard to another high end X58 board, unless I could get a good deal for the used one.

MrS

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Scanning for our furry friends since Jan 2002

... i was thinking of somehow attatching a cpu cooler somehow to the metal backplate of the first card see if that has any effect on cooling the heatsink
not sure how i'm going to do that yet though

Ian

Dont even think about it :) To do any kind of non-stock cooling attached to the card, you will need to take off the stock cooler to get at the X-Plates. Doing that exposes the VRMs, and you get into a world of hurt. You can get "cooler cards" that fit expansion slots pointing up at the Card (with stock cooler still attatched), but frankly they more look nice than any practical use.

To cool a 5970 you need targeted, direct cooling onto both the GPU and the VRMs. Its not just the two GPUs to consider, all VRM locations on the PCB need to be sorted as well. On triple fan third party solutions (eg accelero), there are multiple heat sinks, covering not just GPUs, but one heatsink per VRM location. Hence the various triple fan or waterblock third party solutions. Home grown attempts without the stock cooler still attatched will result in one melted card ...

If you try to attatch a CPU cooler to the X-Plates you will likely break the PCB, or at best not cool the VRMs and the latter will litteraly melt its connections.

.... by the way i take it the red openings at the end are intake holes as i was thinking of sticking a fan pointing directly into them too lol ....

The intake grill is inside the case, the output grill is the one on the back of the case. So to use external fans in that way you need to take off the side of the case, wrecking the over-pressure principle need to push the airflow in the case. Thats even if there is enough room to position the fan at the back of the card inside the case without chewing up cables or creating static interference.

Regards
Zy

hi,

crossfire just allows me to get both cards working without having to make dummy plugs or anything else
always wonderd if theres a scaling differance mind you as crossfiring cards hurts there doubling up performance
i learned that when x-firing 3three 4890's the first card would do around 100,000 credits a day add another and that only went up to just under 180,000 and if you added the third it would pretty much peak at 240,000 instead of the 300,000 you might have thought
so as i say i often wondered if by not x-firing them then they would actually double up but couldnt be bothered doing the testing or making the dummy plugs lol

no i wasnt going to disasembly the card in any way just place the cooler on the black back plate somehow lol

see the problem is that its only one of the cores out of the four thats hitting 90 degrees the others sit around 85 to 87 but as soon as that core tips over the 90 degree mark then the fans become very noisy
and the ambient temp in the room can have a differance as it nudges up a degree so does the card and hay presto your just over 90 degrees again

so really i'm not looking for 10 degrees or anything just keeping that one core down to 85 degrees with the rest would make me happy as the fans although audible are not deafening

the overpressure principle doesnt work with this box mainly because i cant get the side on with the cpu cooler which is huge
plus i've always found aiming multiple fans directly inside the open side of the case kept the temps lower than closing everything up and forcing air through the box

i've been dealing with computers as a hobby for 30 years and have got to the stage now where it doesnt have to look pretty or conform to logic if it defies logic and works thats good enough for me lol

ian

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....Please Join team Scotland HERE

..... crossfire just allows me to get both cards working without having to make dummy plugs or anything else .... always wonderd if theres a scaling differance mind you as crossfiring cards hurts there doubling up performance
i learned that when x-firing 3three 4890's the first card would do around 100,000 credits a day add another and that only went up to just under 180,000 and if you added the third it would pretty much peak at 240,000 instead of the 300,000 you might have thought .....

Scaling is an issue with dual GPUs - whether its NVidia or AMD - however certainly NVidia do tend to scale better as CUDA is more mature than APP. I did try to sort out the cards using dummy plugs, but failed miserably - I could not get Windows to play nice in the config screen re VGA devices. In the end idleness took over and slapped on the extended crossfire strip. ETA is more experienced at that kind of stuff than I am, he may be able to help with dummy plugs. I cant, I failed long ago on that one :)

... i've been dealing with computers as a hobby for 30 years and have got to the stage now where it doesnt have to look pretty or conform to logic if it defies logic and works thats good enough for me lol ....

I noticed rofl ..... gives me the screaming ebie-jeebees to even think down that road, let alone watch you gallop down it :) I'm a committed coward where £1000 of graphics cards are concerned :)

.... see the problem is that its only one of the cores out of the four thats hitting 90 degrees the others sit around 85 to 87 but as soon as that core tips over the 90 degree mark then the fans become very noisy
and the ambient temp in the room can have a differance as it nudges up a degree so does the card and hay presto your just over 90 degrees again ...

Unfortunately that fourth GPU heating up and its VRMs are a 5970 characteristic - it only comes into play when pushing the card hard with higher o/c attempts.

Re the cooling .... there's really only one viable alternative .... tower case, and third party coolers. Take solace in the fact that you dont need to go to liquid nitrogeon. Mind you with your "have at 'em" mindset, you might take that as a disappointment rofl :)

Hopefully ETA can give you a steer on dummy plugs - making them is dead easy - I just could not get them sorted properly when using two 5970s. You will gain a fair amount re scaling if you get that done. The scaling is the reason 2x5870s are always "faster" than a single 5970.

Regards
Zy

Now it's my turn for a little: LOL!
To be honest, I have never ever used more than 1 GPU in a machine yet. Personally I find it hard enough to cool one decent high-end card quitely enough, on air. My tuned HD6950 has got a huge Thermalright Shaman attached to it and takes up 4 Slots, I guess. But my case cooling couldn't take another card anyway and my ears can't take a stock cooler.. so i'm happy with that :)

Regarding cooling your HD5970: putting a CPU cooler onto the back of the overheating card will help a little, but probably not much since the heat has to travel quite far until it gets there, meaning removing it doesn't affect the heat source much.
What you could do: grab some fans and some of the old plastic motherboard place holders, if you can. Could be that they still originate from AT case times, can't remember. These plug well into the mounting holes of fans. Your fans prepared in this way can stand on the back of the card. You could also attach some low profile aluminum heat sinks. Taller heat sink wouldn't help much, though.

And reducing voltage would still be king.. but still I don't know if this can be done in software for your cards.

MrS

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Scanning for our furry friends since Jan 2002