ZWO asi183MC CPU Power Spikes

[john_robertson1953]

I purchased asi183MC. Using Win11pro, with Mele quieter3 RDP to Lenovo thinkpad 12 core laptop. Using both Sharpcap v4 and ASI studio. When i connect camera to either software and begin capturing, per Win task mgr, power usage for either software spikes to 60-80% CPU util with overall CPU usage spiking to 95-100%(Mele), causing freezing and eventually RDP disconnect and then re-connect. I’ve installed latest drivers. What’s issue with spiking and need help/ solution to this problem. Please advise.

[admin]

Hi,

so the first thing to check is what CPU usage do you get when there is no RDP involved (ie you are using the laptop from its keyboard and screen)? When you are running a fairly high resolution camera like the 183MC at high frame rates, there is an awful lot of work to do to transfer each image from the one computer to the other. If the RDP software is trying to compress each image update, that could be part of the problem.

Another thing to look into is based on the fact that SharpCap tries to use your graphics card acceleration to help reduce CPU load - usually this is effective, but sometimes the graphics card acceleration might cause problems, and using RDP is one of those situations. There is an option in the first page of the settings to turn off 'hardware acceleration' which might help,

cheers,

Robin

[john_robertson1953]

Hi Robin,
Thanks for ur prompt reply.
Re my initial tests, I’m remotely accessing Mele from my Lenovo laptop. I’m running Sharpcap on the Mele and saving captured files to the Mele’s HD. I’m also running same tests directly on laptop, saving captured files to its HD. The CPU utilization spike begins as soon as i connect camera, prior to capturing.

For instance, per Task mgr, re Mele( 8GBram) 4 core, as soon as I connect camera(USB3), it spikes to 71% load of total 74% load. Once capturing, it spikes to 90% of total 100%. It’s at this point, screen will eventually freeze, and the remote connection is disconnected.

For Lenovo, (16GBram) 10 core processor, when I connect camera in Sharpcap, per task mgr, it’s showing 32% CPU util, 43% while capturing. I can live with this result with Lenovo, but need Mele in order to work remotely.

Btw, I turned off graphics card acceleration and numbers actually went up a few %.

Interestingly I re-ran tests using ZWO asiStudio software, and the results were about 50% less than Sharpcap numbers.

One other point, I own asi183MC, non-cooled so it’s obtaining all of its power from USB3 port connected to respective computer.

Hoping someone has some suggestions.

Thanks in advance.

[admin]

Hi,

Ok, I understand your setup a bit better now. What I meant to ask really was regarding the load if you capture on the 'Mele' laptop, but without remote desktop. Is that a reasonable CPU load on its own with remote desktop pushing it over the edge, or is SharpCap alone capable of causing the problem.

cheers,

Robin

PS. What is the processor in the Mele? You mention 4 core, but there are lots of different possibilities in terms of power for 4 core processors.

[john_robertson1953]

Hi Robin,

I purchased another upgraded Mele mini. Doubled the Ram at 16GB.(see below for computer specs) Ran following tests on Mele directly, no RDP, as u requested.

Seems as if I increased capture area, the CPU util % of SharpCap increased significantly. Hers a table of my results, by color space, by cap area, see below.

Please advise. I would have thought doubling the RAM would have reduced load.

Colour Space Cap Area SharpCap % TotalCPU Usage %
RAW8 5496X3672 74-77 95-100
2744X1836 52-57 68-69
800X600 42-43 54-55
RAW 16 5496X3672 80-85 98-100
2744X1836 60-61 75-78
800X600 45-47 60-61
RGB24 5496X3672 87-91 99-100
2744X1836 80-85 92-94
800X600 45-47 58-

Device name. Astromini
Processor. Intel(R) Celeron(R) N5105 @ 2.00GHz 2.00 GHZ
Installed RAM. 16.0 GB (15.8 GB usable)
Device ID. CE520094-9B55-4ECE-AE33-9A55¢397812D
Product ID. 00330-51484-59776-AAOEM
System type. 64-bit operating system, ×64-based processor
Windows 11pro

[john_robertson1953]

Robin,
For the heck of it, I ran limited tests using Zwo asiStudio studio. Not as many features as sharpcap.
RAW 16. 5496X2672. 45-46% 49%
RAW 8. 5496X3672. 44-45%. 49%

I reran sharpcap RAW16 5496X3672 right after running above. Now showing 70-71%. 78%. Dropped 10-15 % points??

[admin]

Hi,

thanks for the info on the loading at different resolutions - those figures make perfect sense, as the bigger the image, the more work that needs to be done to get it displayed on screen, both by SharpCap and by the operating system. 16 bit modes will naturally take a bit more work than 8 bit modes, since the bit depth needs to be converted before display.

I have just done some performance tests here and there is actually relatively little work being done in the SharpCap code when running a high res ZWO camera in RAW8. Turning off the hardware acceleration does increase the CPU load as it has to take over the work of the GPU. The biggest chunks of CPU work are

* fetching the frame from the ZWO SDK - unavoidable
* Debayering the raw frame to a colour image

If you turn off the debayer of the displayed image (Debayer Preview set to Off) you may find it halves the CPU load for high speed high resolution imaging.

Note that other settings may slow things down a bit - for instance applying a display stretch will use some additional CPU resources.

Of course, there is a fundamental limit - low power CPUs like the celeron will struggle to run high resolution cameras at high speed. ASI studio may have the edge in efficiency in some cases - unfortunately I have already spent some considerable time optimising the performance of SharpCap in the past, so there are hardly any 'quick fixes' available.

cheers,

Robin

[admin]

I just dug into this a bit more and discovered that a feature in SharpCap to reduce the display frame rate if the CPU usage was high has been made much less effective due to some other recent changes.

I am looking into fixing this feature - once fixed you will see the display update less frequently if the total CPU usage goes about 75%.

cheers,

Robin

[john_robertson1953]

I don’t want to get too enthusiastic but I went into memory and increased the high-speed frame cache and the live stacking and display to 4000 MB each. CPU usage percent is down significantly!! Make sense?

[jabbourk]

Similar problem with a different twist - using ASI183MC at full resolution, 1/2000 sec exposure, 10-second video capture, RAW8, I can reach only 7 fps on SharpCap Pro, but 19 fps on ASICap. I am using a Dell OptiPlex with USB3.0, 8GB RAM, i3 4 core CPU, no display! CPU utilization reaches 90% when capturing with SharpCap, but only 40% when capturing with ASICap. I experimented with pretty much every capture and USB parameter, the result remained the same. Any suggestion?

Dr. Kamal Jabbour
YouTube.com/RoosterInnObservatory