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Posts by ExtraTerrestrial Apes

1) Message boards : Number crunching : Tesla K40 & System Upgrade Thoughts? (Message 61450)
Posted 29 Mar 2014 by ExtraTerrestrial Apes
Post:
P.S. If that is an i7 4770 it has an i-GPU which can be used with the Intel OpenCL SDK - I'm running E@H on mine...

Correct, apart from that you don't need the SDK. Any recent driver will do.

MrS
2) Message boards : MilkyWay@home Science : news about Milkyway structure (Message 55629)
Posted 1 Oct 2012 by ExtraTerrestrial Apes
Post:
Hi,

I just stumbled across this paper. They've detected a hydrogen cloud of ultra low density around the Milkyway. However, due to its size the accumulated mass is significant - 10 to 60 billion suns.

I suppose this is significant working with the Milkyway structure and gravity. Can anyone elaborate? Is this old news for you, or does it change everything? Could you use MW@Home to derive properties of this cloud?

Best regards,
MrS
3) Message boards : Number crunching : GPU Radeon 6950 with latest catalyst drivers not supported? (Message 54280)
Posted 1 May 2012 by ExtraTerrestrial Apes
Post:
Shader unlocking is cool, lowering the PowerTune target by 20% is not. The problem: this just lowers the frequency when the card would exceed the limit, but doesn't decrease the voltage. Therefore you don't gain any efficiency. And it only works IF the card would exceed the limit, otherwise you don't gain anything.

If the card is drawing too much power: 1st reduce the voltage at stock clocks. There's lot's of safety margin. Tried 1.00 V at 810 MHz on my unlocked HD6950, no problems. Didn't bother trying any lower, stock is 1.10 V. That will already make it consume at lot less (I guess 20 - 30 W) without a performance loss. You won't reach OC clock speeds, though, but there's no free lunch..

If that's not enough lower the GPU clock a bit and simultaneously lower the voltage further. Efficiency of the card will go up, but performance will go down a bit.

MrS
4) Message boards : Number crunching : GPU Radeon 6950 with latest catalyst drivers not supported? (Message 54265)
Posted 30 Apr 2012 by ExtraTerrestrial Apes
Post:
My only complaint is the power usage. The card alone pulls an extra 200 watts when it's doing work units.

That crunching-power has to come from somewhere, there's no free lunch in computing.

MrS
5) Message boards : Number crunching : GPU Radeon 6950 with latest catalyst drivers not supported? (Message 54224)
Posted 28 Apr 2012 by ExtraTerrestrial Apes
Post:
No driver related problems here with Cat 12.3 and Cat. 12.4 on an unlocked HD6950.

@tex: what's OCN and what problems?

MrS
6) Message boards : Number crunching : 7970 crunching more WUs (Message 54050)
Posted 16 Apr 2012 by ExtraTerrestrial Apes
Post:
I was running my OC'ed HD6970 here, so also plenty of horse power. All it took me to keep it budy was to reserve one core and to run 2 WUs concurrently. The draw back is that this requires and app_info.xml, i.e. in case of a client update you're not getting it automatically.

Besides achieving permanent 99 - 100% GPU utilization (after some time to settle in) during a WU, the ~3s of CPU time at the end of each WU are not wasted on the GPU (it just continues to crunch the other WU in the mean time). With your method and without an app_info you can also achieve maximum GPU utilization during each WU, but you can't work around the CPU time at the end. However, if you use your method with an app_info and 2 concurrent WUs I can not see any benefit over just reserving one core.

MrS
7) Message boards : Number crunching : Video Card choices (Message 53893)
Posted 2 Apr 2012 by ExtraTerrestrial Apes
Post:
The HD4850 is still fine, but getting really old. Sure, it doesn't consume as much power as other cards, but it's also slower. The chip is manufatured in dated 55 nm technology, which is inherently less power efficient than the 5xxx and 6xxx series in 40 nm.

Personly I sold my HD4870 some time ago to a gamer on a budget, as I figured it was not power efficient for 24/7 crunching any more.. for me, at least.

MrS
8) Message boards : Number crunching : AMD 7970 GFLOPS question (Message 53873)
Posted 31 Mar 2012 by ExtraTerrestrial Apes
Post:
There you have it. That's why I asked whether your GPU was downclocked - it is, sometimes. And if it is, you'll see the slow crunching speed. Otherwise your card is fine.

How did you set the overclock? Currently I'm using Spphire TRIXX, but EVGA Precision or MSI Afterburner should all work well.

MrS
9) Message boards : Number crunching : GPU Performance? (Message 53865)
Posted 30 Mar 2012 by ExtraTerrestrial Apes
Post:
I don't have a good list at hand, but performance at MW is directly proportional to the theoretical maximum double precision performance. Which is 1/16th the single precisions performance (usually only this number is quoted in reviews) for HD77x0 and HD78x0, so these are actually rather bad at MW. For your GTX460 it's 1/12th - better, but still inefficient. GTX680 even goes as far 1/24 *ouch*

For HD79x0 and HD69x0 it's 1/4th, that's where their strength at MW comes from. Any AMD capable of double precision older than these has a ration of 1/5, which is still very good.

In essence: you can calculate the performance of pretty much any AMD by the following:
clock speed * number of shaders * double precision fraction

There's a slight exception to this rule: currently the HD7xx0 have to run less efficient code, so there's still some untapped potential left in them.

MrS
10) Message boards : Number crunching : AMD 7970 GFLOPS question (Message 53864)
Posted 30 Mar 2012 by ExtraTerrestrial Apes
Post:
One of your current tasks reports:
"Estimated AMD GPU GFLOP/s: 4608 SP GFLOP/s, 1152 DP FLOP/s"

so you should be fine. Maybe your GPU was underclocked before?
BTW: this is Milkyway@Home ;)

MrS
11) Message boards : Number crunching : 6990 (Message 53846)
Posted 29 Mar 2012 by ExtraTerrestrial Apes
Post:
Or did you mean HD6970 instead of HD6790? Confusing.. but they're totally different beasts. The former has DP and is quite a MW-monster.

MrS
12) Message boards : Number crunching : app_info.xml file for 2 WUs/nVIDIA GPU ? (Message 53830)
Posted 28 Mar 2012 by ExtraTerrestrial Apes
Post:
In principle correct, but MW doesn't need much memory. I think any card with DP should be fine running 2 WUs at once. And running more than that is pointless at MW anyway.

MrS
13) Message boards : Number crunching : gpu app (Message 53796)
Posted 25 Mar 2012 by ExtraTerrestrial Apes
Post:
Any app that you may know of out their for one without double?

Just in case it wasn't clear: POEM's also on that list.

MrS
14) Message boards : Number crunching : gpu app (Message 53792)
Posted 25 Mar 2012 by ExtraTerrestrial Apes
Post:
You can put your GPU to good use (IMHO) at POEM@Home, they've recently released an OpenCL app for all (relatively modern) AMDs. BOINC 7 needed, though.

MrS
15) Message boards : Number crunching : 6990 (Message 53791)
Posted 25 Mar 2012 by ExtraTerrestrial Apes
Post:
That's just like mine, except for this line:

<version_num>102</version_num>
<plan_class>ati14</plan_class>

I don' think it's needed, though.

MrS
16) Message boards : Number crunching : 6990 (Message 53777)
Posted 25 Mar 2012 by ExtraTerrestrial Apes
Post:
Sadly there's no official way to disable separation tasks on the CPU if you've got a GPU running. Some projects allow such settings in your account. However, you could use an app_info for the GPU tasks. This would allow to crunch 2 GPU WUs per card simulataneously, so you can get rid of the break between WUs. Improves throughput on fast GPUs significantly.

I could give you such an app_info. This would stop you from running CPU tasks for MW at all. It would probably be better to use the CPU for n-body tasks (which GPUs can't run). To do this something has to be added to the app_info, which I'm not familiar with.

Edit: on my rig I used to run 7 CPU tasks on my i7 2600K @ 4.0 GHz and 2 WUs on the GPU. CPU support was more than enough, GPU utilization 99-100%.

@Semtex: due to technical reasons (I'd say AMDs fault) the HD79x0 are running less optimized code, so there's there's still untapped potential left.

MrS
17) Message boards : Number crunching : 6990 (Message 53758)
Posted 24 Mar 2012 by ExtraTerrestrial Apes
Post:
HD6970, 910 MHz core clock: 2 WUs every 100 s. 1.10 V for the chip, so power consumption may be around ~150 W. Cooled by a Thermalright Shaman - cool & quiet. Sorry, no video ;)

MrS
18) Message boards : Number crunching : 6990 (Message 53754)
Posted 23 Mar 2012 by ExtraTerrestrial Apes
Post:
What's the point of going through the hassle of making a video of the card crunching?

MrS
19) Message boards : Number crunching : 7970 crunching more WUs (Message 53733)
Posted 21 Mar 2012 by ExtraTerrestrial Apes
Post:
You can also set this in the account setting for MW now.

MRS
20) Message boards : Number crunching : 4870 problems (Message 53709)
Posted 18 Mar 2012 by ExtraTerrestrial Apes
Post:
THe card would work with either CC 12.2 or 12.1 (and others) in Win 7/Vista. However, there was something special about XP. Sorry, can't remember what. It's almost certainly some older driver which is needed.

MrS


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