Yesterday I changed my old HD 7750 card and installed an RX 480 8Gb card instead.
This is in my AMD machine with only 2 CPU cores:
https://setiathome.berkeley.edu/show_host_detail.php?hostid=8121459

My thoughts was to not run any CPU tasks only GPU tasks, was planing on runnig at least 3 GPU tasks.

But now to my problem, everytime I try to run more than 2 GPU tasks something happens and all workunits comes to 100% done in a very short runtime.
Running 2 tasks with vlar's takes aprox 18-20min/task but when I run 3 tasks they are done in 29-40 seconds.
The tasks end up as Validation inconclusive or Invalid.
I'm using the following command line:

-tt 300 --period_iterations_num 3 -sbs 1024 -spike_fft_thresh 4096 -tune 1 64 1 4 -oclfft_tune_gr 256 -oclfft_tune_lr 16 -oclfft_tune_wg 256 -oclfft_tune_ls 512 -oclfft_tune_bn 64 -oclfft_tune_cw 64

But I have also tried without any command line and the result is the same.

Here are my app_config.xml

When running 2 GPU Tasks
<app_config>
<app>
<name>setiathome_v8</name>
<gpu_versions>
<gpu_usage>0.5</gpu_usage>
<cpu_usage>1.0</cpu_usage>
</gpu_versions>
</app>
</app_config>

When running 3 GPU Tasks
<app_config>
<app>
<name>setiathome_v8</name>
<gpu_versions>
<gpu_usage>0.33</gpu_usage>
<cpu_usage>0.66</cpu_usage>
</gpu_versions>
</app>
</app_config>

Also tried 4 GPU task
<app_config>
<app>
<name>setiathome_v8</name>
<gpu_versions>
<gpu_usage>0.25</gpu_usage>
<cpu_usage>0.50</cpu_usage>
</gpu_versions>
</app>
</app_config>

I also tried the -high_prec_timer -use_sleep command in my command line but with no effect.

Any ideas or is this because the crappy AMD 2 Core CPU...???

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

Your CPU core need to feed your GPU....so maybe feeding 3 GPU with only 2 CPU is too much....
Check your PCIe bandwith utilization with nvidia-settings.

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Your CPU core need to feed your GPU....so maybe feeding 3 GPU with only 2 CPU is too much....
Check your PCIe bandwith utilization with nvidia-settings.

Yes, that could surley be the case.
I will check PCIe bandwith util. when I get home after work today.
Not sure how I can check that on an Radeon card?

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

This is one of the most dramatic demonstrations of trying to do too much work on a system.
I very much doubt that it is anything to do with PCI bandwidth, but to do with the lack of resources from the CPU.
What was the time per task running a single task per GPU?
What was the time per task running two tasks per GPU?

---

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

This is one of the most dramatic demonstrations of trying to do too much work on a system.
I very much doubt that it is anything to do with PCI bandwidth, but to do with the lack of resources from the CPU.
What was the time per task running a single task per GPU?
What was the time per task running two tasks per GPU?

You can't blame a guy for trying :-)
I left the computer with 3 tasks running because our dog which has epilepsy had a seizure yesterday evening.
Then I forgot about the computer and went to bed, woke up at 4 o'clock thinking Ohhh shit!!!

Running a single vlar task took around 9 min
Running 2 vlar tasks takes around 15-17 min/task

I'm also quite sure that It's because lack of resources from the CPU, but I thought I might ask if someone had any ideas anyhow.

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

With those times it would appear that 2-per is the sweet-spot for productivity on your system.
(Note, this does not mean that the same GPU running on a CPU with more ores would limit at 2-per.)

---

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

With those times it would appear that 2-per is the sweet-spot for productivity on your system.
(Note, this does not mean that the same GPU running on a CPU with more ores would limit at 2-per.)

Yes that seems to be it, running 2 Tasks now.

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

Ok, just now I upgraded the AMD machine with a A8-6600K 4 core CPU.
Just tried to run 3 GPU task with 3 free CPU cores with the same result as with my 2 Core CPU.
The tasks end up as invalid and they are 100% done in just seconds.

Maybe it's the RX480 card that doesn't like more than 2 tasks?
Anyone got any ideas?

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

I have a A10-6700 CPU that AMD says has 4 cores. The Windows 10 task manager says that it has 2 cores and 4 logical processors. In effect, it accepts to run only 2 BOINC CPU tasks plus 1 GPU task on its GTX 1050 board.
Tullio

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I checked in CPU-z and it says 4 cores and 4 threads.

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

It is sold as a Quad-Core processor. I doubt both Amazon and Newegg sell these things on false information.

But else, http://cpuboss.com/cpu/AMD-A8-6600K

summary
Clock speed 	3.9 GHz
Turbo clock speed 	4.2 GHz
Cores 	Quad core
Is unlocked 	Yes

details
Architecture 	x86-64
Threads 	4 threads
L2 cache 	4 MB
L2 cache per core 	1 MB/core
L3 cache 	None
Manufacture process 	32 nm
Max CPUs 	1
Operating temperature 	Unknown - 74°C

Should be enough information.

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Gonna try running 2 CPU tasks and 2 GPU tasks and see if that works, if yes than it's something with the RX 480 card.

EDIT: Running 2 CPU tasks and 2 GPU tasks works perfect no problems.
So seems that there is something to do with the RX 480 card.
Surley a RX 480 card must be able to handle more than 2 tasks?

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

The latest applications are far more processor hungry than many of the older applications were, so 2-per is probably a good starting point

---

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

I am a Linux user, not a Windows specialist. But the Windows 10 Task Manager says that the A10-6700 CPU has one socket, 2 cores and 4 logical processors.
Tullio

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I'm gonna try a different app on the GPU (r3486) and see how that goes.

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

Well no luck with older application (r3486) still same problem.
Hmm I find it very strange that an RX 480 card will not run more than 2 tasks...

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

Have you tried running three without all those cmdline settings? Try removing all the cmdline settings and just use the cmdline -instances_per_device 3 to run three instances.

Have you tried running three without all those cmdline settings? Try removing all the cmdline settings and just use the cmdline -instances_per_device 3 to run three instances.

Yes, I just tried that with no luck :-(
I tried my usual cmd line with complement -instances_per_device 3 no change
Tried only -instances_per_device 3 in cmd line no change.

This is quite strange, I'm starting to think maybe a faulty Rx 480 card....

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006

More likely it's just a faulty driver, unless you can find someone else that can run 3. Oh well, you probably wouldn't see much of a speedup with 3 anyway. At least you can run 2, the last I heard the Hawaii GPUs can't run more than 1 without producing Bad results and errors.

Yeah, I guess I will have to settle with running 2 GPU tasks and 2 CPU tasks.
But I'm not he guy who just gives up, I've updated the driver let's see what happens.....:-)

---

"SETI is probably the most important quest of our time,
and it amazes me that governments and corporations
are not supporting it sufficiently."- Arthur C. Clarke 2006