Uneven usage of GPUs

k, my assumption was wrong..

then try to free one cpu core as previously mentioned.
at boinc manager - computing preferences, set the value of "On multiprocessor systems, use at most" to 84 % and look if the times drop.

edit:
(ups, was a little late...)
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I had already set it to 95%, but now have changed it to 50% as you suggested Bilbg/Highlander, will see how it goes.

Update: Setting aside 3 cores doesn't seem to have any effect

What CPU load you see (in Windows Task Manager - Performance tab) on all cores when this is set to 50%?
Do you see only 3 CPU tasks running (in BOINC Manager - Tasks, in Windows Task Manager - Processes)?

Try even lower setting as 1% (I'm not sure will this use 0 or 1 core (i.e. no CPU tasks running at all or just one CPU task))

Change for test to <count>1</count> (make copy of original app_info.xml for easy return)


Also check what is 'angle range', only compare times for "similar" AR tasks:
"WU true angle range is" in stderr.txt (in ....\BOINC\slots\ while the GPU tasks run)
<true_angle_range> in the task/WU file

There are very few long running GPU tasks, in fact I found only one (after a few minutes browsing):
http://setiathome.berkeley.edu/result.php?resultid=2659629186
Can you give more links to long running GPU tasks?

jason_gee (the main programmer of the CUDA app you are using): http://setiathome.berkeley.edu/show_user.php?userid=8534984
... often suggest running DPC Latency Checker to check for bad behaving drivers in the system:
http://www.thesycon.de/deu/latency_check.shtml

http://setiathome.berkeley.edu/forum_thread.php?id=68151&postid=1240292#1240292
http://setiathome.berkeley.edu/forum_thread.php?id=67270&postid=1207226#1207226
http://setiathome.berkeley.edu/forum_thread.php?id=66787&postid=1189977#1189977

http://setiathome.berkeley.edu/forum_thread.php?id=66241&postid=1185224#1185224
http://setiathome.berkeley.edu/forum_thread.php?id=66241&postid=1184322#1184322


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

With 3 cores active, I was getting the load that varied between 50 and 55%. Setting it to run just 1 core (1% setting) gave the load between 16 and 21%. Changing the count to 1 too didn't seem to bring about any change.

Here are few more WUs with similar AR

http://setiathome.berkeley.edu/result.php?resultid=2659629612
http://setiathome.berkeley.edu/result.php?resultid=2659629560
http://setiathome.berkeley.edu/result.php?resultid=2659619623
http://setiathome.berkeley.edu/result.php?resultid=2659619621

I will have to wait until I get back home before I can use the DPC Latency Checker.

If you like to play with video drivers - many people suggested in the past that this driver worked best
(I can't confirm by personal experience, I do not have CUDA GPU)

NVIDIA DRIVERS 266.58 WHQL - Windows XP 64-bit
http://www.nvidia.com/object/winxp64-266.58-whql-driver.html


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

Here are my observations after running DPC Latency Checker.

1. I was getting high reading (max of 22k microsec) at frequent intervals. Following their suggestion, I disabled the network card and the frequency and the maximum values dropped.

2. I also noticed the EVGA Precision X was using a high % of CPU so shut that down as well which further reduced the latency.

3. Next to be disabled were the nVidia HD Audio. After this I started getting low reading with max of 1850 microsec.

I left the system running for sometime, during which a blank screen saver that I had set, kicked in. Upon returning, I logged back in and although the latency was still under 1000 microsec, one of the GPU had started a slow motion stunt.

So the next step was to disable the screen saver.

I did a drivesweep and fresh installation of the LAN driver. And just to be sure, I did a clean installation of the graphics driver with both the cards in the system. I enabled the network card and the latency was within permissible levels with occasional spikes.

Finally I put back the max CPU cores to be used back at 100% and the both the GPUs, as of now have been crunching without any hiccups since last night.

Currently disabled items - nVidia HD Audio, screen saver, EVGA Precision X.

Currently disabled items - nVidia HD Audio, screen saver, EVGA Precision X.

From past experiences, i'd blame the screen saver.
I haven't bothered with one for 10+ years.

From past experiences, i'd blame the screen saver.
I haven't bothered with one for 10+ years.

I never had any issues with screensavers before and never thought it would cause such a massive overhead on the system. I will continue to leave it disabled and see how things go.

The rig has been under observation for many hours now and still seems to be doing well than before, and hope it stays that way. Not really sure if the nVidia HD Audio has any adverse effects but I shall keep it disabled, and also the screensaver. The network card has to be active for obvious reasons.

I have to thank you all for your advice and expertise. And thanks to BilBg for the Latency Checker. There are still some spikes now and then but the crunching looks smooth.

screensaver you say? That might be a clue. Do you have your power settings set to never turn off monitor and always disable any screensaver including the BOINC/seti ones.
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End terrorism by building a school

... Latency Checker. There are still some spikes now and then but the crunching looks smooth.

Here's another data point. Phenom II 945, Ripjaws F3-10666CL7D-8GBXH, ASRock N68C-GS FX (1000MHz HT, 1600MHz IMC).

Running dpc latency checker gave me values around 80 - 110 micro-s.

I changed my bios settings for mem timings to all auto--speed and timings. Previously it was running at 1333 7-7-7-21 (which it is rated for under an XMP profile), "auto" wanted it to 1066 7-7-7-20 which is JEDEC #2 (so says cpu-z).

Latency checker then reported values 15-30.

I tried tightening the timings to 6-6-6-auto, which runs, but the latency goes back up to ~100.

Maybe the Phenom IMC works better with standard JEDEC timings?

... Latency Checker. There are still some spikes now and then but the crunching looks smooth.
Did you see/read also about "PCI latency timer BIOS entry" (mine is set to 128):

Unfortunately the BIOS does give the option to set the PCI latency timer.

Has anyone come across the following message under status in the Tasks list - 'Waiting to run (0.04 CPUs + x.xx NVIDIA GPUs) (waiting for GPU memory)', even though GPU-Z reports memory usage at around 50%?

I had this issue before, in my case happens when for some reason the nvidia driver is corrupted, for example if you try to do remote access with RDP. Normaly restarting the computers solve the problem.

I had this issue before, in my case happens when for some reason the nvidia driver is corrupted, for example if you try to do remote access with RDP. Normaly restarting the computers solve the problem.

I use RealVNC to connect to this rig, however, it never used to give this message. And yes, restarting the rig solves the issue until I access it again. Hopefully a clean reinstallation of the graphics driver will solve this.