64bit won't work on my older Xeon CPU

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james_ca
Posts: 3
Joined: Sat Jul 31, 2021 4:06 am

Re: 64bit won't work on my older Xeon CPU

#11

Post by james_ca »

I should probably add that by "capture buffers" I'm talking about the "high speed frame cache." I also have this same version of SharpCap Pro running on a Core i3 notebook computer and there I can set the frame cache to greater than 4GB (I've got it set to 9GB out of 20GB of available memory).

Maybe the cache size is limited to one half (approximately) of the available memory? My mini PC that does not support AVX has 8GB of DRAM and that would suggest a maximum size of 4GB (maybe?). However, it seems stuck at 3GB (maximum) which suggests that perhaps SharpCap Pro is reserving 1GB for the app and 3GB for the memory cache (or 4GB total as if it were a 32-bit version of the app).
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Re: 64bit won't work on my older Xeon CPU

#12

Post by admin »

Hi,

the total of the two types of memory is limited to a maximum of 50% of system RAM, so with 8Gb RAM you have a maximum of 4Gb between the two types, which can be split 3Gb/1Gb, 2Gb/2Gb, 1Gb/3Gb, etc. Neither type can be set below 1Gb, as that can cause issues with processing images from high resolution cameras.

The requirement to keep below 1/2 of total memory helps ensure that there is enough memory left for the operating system and other applications to avoid swapping too much. I guess I could allow a bit more to be allocated once you get past about 12Gb total memory, but at ~8Gb I think the 50/50 split is about right.

cheers,

Robin
james_ca
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Joined: Sat Jul 31, 2021 4:06 am

Re: 64bit won't work on my older Xeon CPU

#13

Post by james_ca »

Robin, thanks for the quick response and explanation. I guess I read your statement in the memory dialog as indicating that the 50 percent limitation only applied to those who hadn't upgraded to the Pro version.

It would, however, make sense if you could use more than 50 percent on a system with 16 or more gigabytes of DRAM. Also, would it be possible to combine the high speed frame and live stacking caches into a single memory pool? That way either function could grow to whatever was needed at any particular time. Frankly, I never use the live stacking feature, I only use SharpCap for planetary image capture and lucky imaging of DSOs and with a 20 mega pixel camera every megabyte of cache memory is helpful.
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Re: 64bit won't work on my older Xeon CPU

#14

Post by admin »

Hi,

I've thought about trying to merge the two pools of memory, but it is critical to keep the frame cache from taking all the memory otherwise there may not be enough to process/display the frames, so you end up having to ring fence part of a combined pool anyway, which really means you haven't achieved much.

I will try setting the maximum to half of physical memory or physical memory - 6Gb, whichever is larger.

cheers,

Robin
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