SSD PCI-e ? , which intel i7 for my new PC

[NGC7789]

I notice that the CPU score always drops 4-5% the second and third time the Benchmark is run. This occurs in both PI and Windows. Anyone seen this?

Yes I have noticed this, although it's not every time. I experimented with setting my CPU governor to "performance" (the default is usually "on demand") which seemed to alleviate this but made the system less stable. My guess is that this is due to some CPU throttling due to heat or other factors.

In the end I have to force myself to stop running benchmarks and get back to processing images. If only I had new data

[vicent_peris]

Hi Max,

At least in Fedora the default system temporary folder (/tmp) works on RAM, so setting the swap folder to /tmp should work as a RAM disk. The main advantage of using /tmp is that the system automatically resizes the size of the disk according to the actual needs.

It's strange to me that you loose CPU performance when setting several threads for swapping... In my computer I set 8 threads and it does not affect CPU performance, while swap performance is increased by 300% compared to a single thread.


Best regards,
Vicent.

[jkmorse]

I have my "best" results in the benchmark by pointing to my 16Gb ramdisk 4 times (total memory 32Gb).  In answer to your question, it is definitely faster than only pointing to the ramdisk twice. 

I need to try Vincent's proposal to use a /tmp file instead and see if Linux Mint 17.2 does the same as Fedora. 

Even though my times do go down a bit in the benchmark, I also point to two different 128 Gb swap files, one on each of two different SSD drives, to ensure I never have a situation where I run out of memory.  That may be overkill but I am willing to take a small performance hit to ensure that my processes always complete. 

For what its' worth,

Jim

[vicent_peris]

If you're working with large images, I would recommend a fast M.2 disk. Samsung just released the Pro 950 at a very good price ($350 512GB), reads at 2.5GB/s and writes at 1.5GB/s. You can also put several of these disks in your system and tell PixInsight to write to them in parallel. Take a look at this article:

http://www.thessdreview.com/daily-news/latest-buzz/samsungs-newest-950-pro-consumer-m-2-ssd-capable-of-2-5gbs/


V.

[NGC7789]

Ubuntu does not put /tmp in ram by default (at least it didn't when I started) but it's easy enough to do. In fact that is how I am configured precisely because of the sizing limitations Vicent described.

I use /tmp in memory plus an SSD as my swap, two threads each. Don't have the option of fancy new-fangled M.2 disks on my system

[mmirot]

I am not have the best luck with Ubuntu.

I got the best overall performance by doing the procedure that Juan recommend back in 2011

ll preview stored states stay in RAM. To store a preview's current volatile state, use the Preview > Store command. In this way you can accumulate a series of processes on a preview, just as you work with a main view. Naturally, since everything is kept in RAM, you'll exhaust it quickly if your images are large.

On UNIX and Linux we have tmpfs (temporary filesystem). /dev/tmpfs can be mounted on any directory to generate a dynamic RAM disk. It is very easy and of course it is absolutely stable. For example, the following commands:

cd ~
mkdir MySwapDir
su -c 'mount -t tmpfs -o size=4G /dev/tmpfs MySwapDir'

This got 11k total with 10k CPU using the created MySwapDir.  However,  change was not permanent. It reverted to swaps around 4000.

I deleted the ramdisk and recreated it. The swap went  back up 10x to 40000. However, the process speed was again impared.
CPU score went down to 7500( 10,000 is typical in Windows.)

I think I will try Fedora. I don't like Ubuntu.

Max

Max

[lucchett]

This is the way I also use to manage ramdisks.

You need to put an entry in fstab to make the change permanent.

the following worked for me and it is easy:

sudo mkdir -p /media/ramdisk sudo mount -t tmpfs -o size=2048M tmpfs /media/ramdisk
grep /media/ramdisk /etc/mtab | sudo tee -a /etc/fstab

just check your fstab before rebooting, a damaged file could prevent you to boot.

Andrea 

[jkmorse]

PixInsight Resources has a nice little tutorial on building a ramdisk which I used, along with a couple of SSD swap files.  Not sure if its the fastest I could tweak out, but practical day to day PI processes run exceedingly quickly in my Linux Mint 17.2 system, especially compared to what I was getting in Windows 10.

[mmirot]

Smoke'n fast with Fedora 22. I am hitting in the high 12K benchmark totals.
I even had a run or two making 13K total benchmarks.   That's as high as many dual Xeons!

Mainly the difference is in the swap rates between Windows and Fedora as expected.
I see transfer rates around 40,000-45,000 in Fedora.
It is about half that in Windows.  CPU benchmarks are about the same.

( I am overclocking the I7 5930K CPU at 4.2GHZ ( Stock is 3.5GHZ ). I could go higher but speed kills. CPU benchmark = 10.5K)

Max

[NGC7789]

Smoke'n fast with Fedora 22. I am hitting in the high 12K benchmark totals.
I even had a run or two making 13K total benchmarks.   That's as high as many dual Xeons!

Mainly the difference is in the swap rates between Windows and Fedora as expected.
I see transfer rates around 40,000-45,000 in Fedora.
It is about half that in Windows.  CPU benchmarks are about the same.

( I am overclocking the I7 5930K CPU at 4.2GHZ ( Stock is 3.5GHZ ). I could go higher but speed kills. CPU benchmark = 10.5K)

Max

That's great! Congrats on your tweaked out system. As for overclocking I think a modest overclock like you have is a good value and easy to achieve. Going for more is a fools errand. It's not worth the performance for the aggravation IMHO. After all it's really about the images, not hot-rodding our PCs.