Is this Intel i7 machine good for LTSpice?

In article <k4pc5ad6p89qps1blou358m1s2lof9q7ij@4ax.com>, 
jeffl@cruzio.com says...
> 
> On Sun, 02 Nov 2014 07:25:49 -0800, Joerg <news@analogconsultants.com>
> wrote:
> 
> LTspice benchmark on various machines:
> <http://fetting.se/images/PC%20Speed%20Benchmark%20running%20LTspice%20circuits.pdf>
> 
> >Reason I am looking at these is that I absolutely positively do not want
> >any computer with Windows 8 in here and unfortunately that's what many
> >others come with.
> 
> Windoze 8.1 can be made semi-tolerable by putting the start menu back
> in and making it look like Windoze 7.
> <http://www.classicshell.net>
> I've been installing it on all my customers Windoze 8.1 machines and
> have had no complaints or problems.  If you like wiggly icons on the
> Windoze 8.1 start screen, you can do <Shift><Start>.
> 
> The damage control version of Windoze 10, that is possibly due some
> time in the distant future, restores the start menu:
> <http://windows.microsoft.com/en-us/windows/preview>
> but otherwise currently looks like Windoze 8.1.
> 
> Incidentally, Halloween was the last day that Microsoft will ship
> Windoze 7 licenses to OEM's.
> 
> The Dell XPS 8700 seems like a nice machine.  However, if you want
> performance, I suggest you look at an SSD drive for the OS.
> <http://www.newegg.com/Internal-SSDs/SubCategory/ID-636>
> I've had good luck with Samsung 840 EVO series drives (mostly 250GB).
> The ritual is simple.  I use Acronis True Image 2014 (not 2015) to
> clone the hard disk to the SSD.  I then replace the hard disk with the
> SSD and test everything.  When done, I wipe the hard disk, and install
> it as a 2nd hard disk.  If I need to return everything to stock, I
> have the Acronis True Image 2014 backup image with which to recover
> the initial installation.  Elapsed time on a typical fast system is
> about 1 hr.
> 
> Before buying anything, I suggest you try LTspice on the new machine.
> This is VERY easy with LTspice which doesn't use the registry or
> require admin rights.  Just copy the files to a flash drive and it
> should work.  
> 
> One catch.  LTspice saves its preferences to:
>   C:\windows\scad3.ini
> which has to be writeable.  The fix is to use the 
>   -ini <path> 
> command line switch, which will:
>   Specify an .ini file to use other than %WINDIR%\scad3.ini 
> <http://ltwiki.org/LTspiceHelp/LTspiceHelp/Command_Line_Switches.htm>

I have a 17-xxx  XPS 8700, LTSPICE works just dandy on it.

Jamie

On 11/2/2014 5:28 PM, Jeff Liebermann wrote:
> On Sun, 02 Nov 2014 14:56:04 -0500, rickman <gnuarm@gmail.com> wrote:
>
>>>> One catch.  LTspice saves its preferences to:
>>>>     C:\windows\scad3.ini
>>>> which has to be writeable.  The fix is to use the
>>>>     -ini <path>
>>>> command line switch, which will:
>>>>     Specify an .ini file to use other than %WINDIR%\scad3.ini
>>>> <http://ltwiki.org/LTspiceHelp/LTspiceHelp/Command_Line_Switches.htm>
>
>> I need to note this somewhere.  Writing to the Windows directory is a
>> *very* bad idea.
>
> It was standard procedure in Windoze 3.1, where almost all
> applications dropped pick_a_name.ini files in the C:\Windows\
> directory.

Yes, and Windows 3.1 crashed on a regular basis for about any reason 
whatsoever just like 95, 98 and ME.

MS has been telling developers since Win2000 and maybe since NT to not 
put data files in the Windows or Program Files directories.  Many chose 
to ignore this which wasn't enforced until Vista and became one of the 
things everyone loves to hate about Vista.


> I do have to admit it was handy as the files were easy to
> find and save.  The new and improved versions of Windoze hide these
> config files in either the registry, or bury them 5 directory layers
> deep, where few can find them without specialized tools or inside
> information.

Windows doesn't put anything from an app in the registry.  That is up to 
the app to decide.  Getting to these directories is easy if they used 
the right location, C:\ProgramData.  Instead they continue to use 
C:\Program Files and now with Win8 MS puts the files in the long path 
name you list, but I believe they can be reached transparently through 
the path C:\Program Files  So the best of both worlds.

If the app puts them somewhere else, don't blame windows.


>> I can't tell you how many developers do all sorts of
>> things they aren't supposed to under windows.  That is the actual cause
>> of many problems people have running older software under Windows.  They
>> don't listen to the people providing them with the OS!
>
> LTspice (aka SwitcherCAD) is a rather old program, with many of the
> traditions of Windoze 3.1 still present.  If you don't like that, try
> running some of the various NEC antenna modeling programs, that still
> use the terms "card" and "deck" from the Hollerith punch card era. The
> common mantra is the same everywhere... if it works, don't touch it.

These programs have been updated many, many times since Windows 3.1. 
Windows NT, 2k, XP, Vista, 7, 8 and 8.1 aren't even the same OS as the 
3.1 tree which was ended when XP was released.  Stick with the old 
habits and blame yourself or your program maintainer.

I use some open source Windows software that does the same crap and I am 
very vocal about the cause and the fix for the problem.  Few of the 
developers are interested though.  Now that 8 makes this (using Program 
Files for data) work adequately they no longer have a need to change it.

If you are relying on programming habits from over 20 years ago, then 
you will have to stew in your own soup.


> Looking at the benchmarks at:
> <http://fetting.se/images/PC%20Speed%20Benchmark%20running%20LTspice%20circuits.pdf>
> my Dell Optiplex 755 clunker runs the 3 benchmarks at:
>     14.5   7.6   3.6
> If I upgrade to the fastest machine on the list:
>      4.0   2.9   1.0
> or roughly 3 times faster.  Might be worth $1200+.
>
> The database is at:
> <https://groups.yahoo.com/neo/groups/LTspice/database/2/edit>
> and shows no Windoze 8.1 benchmarks and no SSD, so those will remain
> an unknown.  The benchmark files and instructions are at:
> <https://groups.yahoo.com/neo/groups/LTspice/files/%20Examples/Benchmark/>
> If you run the benchmark, be sure to add it to the database.

SSD is great for anything that uses virtual memory (god forbid) or runs 
for a short time after taking time to load.  I would not expect spice to 
have issues with disk speed except I guess the graph data is stored on 
disk maybe?  I seem to recall some of my simulations generating a lot of 
data which would have easily overflowed the 3 GB of RAM in my machine 
after the OS got done with it.

-- 

Rick

I'm on a quad core Xeon, which means I can have 8 threads. Also a Supermicro 
motherboard with 32G of error correcting RAM. Basically a low end 
workstation. 

LT Spice has been multithreaded for about 5 years now, but the nature of 
spice simulation won't lead to a linear speed up with the number of cores. 
In fact, your setting of three makes sense based on system monitor analysis.

If you go with error detection and correction, you need a server grade mobo 
like a Supermicro. Not all boards that can use such RAM have the ability to 
report back on the amount of correction that occurs.

Regarding:
"I have spent too many hours this weekend tweaking the transient
response of a semi-hysteretic (we call it "hysterical") switchmode
constant-current source. There are about 8 interacting knobs to turn.
At 30 seconds per run, understanding the interactions is impossible."

Spice is not a design tool. It is a verification tool.



 
 

Joerg wrote:

> 
> There are so many variants of graphics cards that it would require tons
> of work for Mike's team.
> 

It isn't the graphics card as much as the standard of acceleration. ATI and 
Nvidia use different standards.

NGspice has Cuda support, which means you need Nvidia.
> http://ngspice.sourceforge.net/

You also need an OS that supports CUDA.

On Sun, 02 Nov 2014 20:04:44 -0800, miso <miso@sushi.com> wrote:

>I'm on a quad core Xeon, which means I can have 8 threads. Also a Supermicro 
>motherboard with 32G of error correcting RAM. Basically a low end 
>workstation. 
>
>LT Spice has been multithreaded for about 5 years now, but the nature of 
>spice simulation won't lead to a linear speed up with the number of cores. 
>In fact, your setting of three makes sense based on system monitor analysis.
>
>If you go with error detection and correction, you need a server grade mobo 
>like a Supermicro. Not all boards that can use such RAM have the ability to 
>report back on the amount of correction that occurs.
>
>Regarding:
>"I have spent too many hours this weekend tweaking the transient
>response of a semi-hysteretic (we call it "hysterical") switchmode
>constant-current source. There are about 8 interacting knobs to turn.
>At 30 seconds per run, understanding the interactions is impossible."
>
>Spice is not a design tool. It is a verification tool.
>
>

Of course it's a design tool. Why spend a half hour cranking out a
voltage divider network with a calculator, when you can Spice and
fiddle a solution in a few minutes?

Is a calculator a design tool? Is an equation a design tool?


-- 

John Larkin         Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Jeff Liebermann wrote:

> On Sun, 02 Nov 2014 12:27:52 -0800, DecadentLinuxUserNumeroUno
> <DLU1@DecadentLinuxUser.org> wrote:
> 
>>  Even better than those are the mSATA drives and now, the best...  the
>>M.2 drives.
>>  Not much bigger than a couple of air mail stamps (I date myself).
>>  Way faster than the 2.5" form factor SSD "laptop drive" replacement
>>family.
> 
> The SSD drive I recommended comes in both SATA3 and mSATA
> configurations:
> 
<http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/ssd840evo/overview_mSATA.html>
> 
<http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/ssd840evo/overview.html>
> The specs look fairly close:
> 
<http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/ssd840evo/specifications.html>
> 
> I have an older mSATA drive in my Acer C720 running Linux.  Very very
> very very fast, but I haven't compared it with a SATA3 drive.
> 

The Samsung 840 series has a speed bug. The fix is in flux, so it is best to 
do an internet search for this issue. Samsung released a windows program to 
"fix" the problem. 

I unfortunately have the 840 in this PC but I run linux, so their fix isn't 
so handy.

On Sun, 02 Nov 2014 21:08:42 -0800, miso <miso@sushi.com> wrote:

>The Samsung 840 series has a speed bug. The fix is in flux, so it is best to 
>do an internet search for this issue. Samsung released a windows program to 
>"fix" the problem. 
>
>I unfortunately have the 840 in this PC but I run linux, so their fix isn't 
>so handy.

The Linux fix is on the Samsung web pile in the form of a bootable CD:
<http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/support/downloads.html>
Near bottom of page.  I've only done the Windoze version once.  When
it works, it's quite simple.  However, if the "advanced mode" is
required, it's an ordeal.  As always, make an image backup before
doing anything this radical.

-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

On Sun, 02 Nov 2014 21:08:42 -0800, miso <miso@sushi.com> Gave us:

SNIP 
>
>The Samsung 840 series has a speed bug. The fix is in flux, so it is best to 
>do an internet search for this issue. Samsung released a windows program to 
>"fix" the problem. 

  No bugs in these speed demons from them...

http://www.amazon.com/Samsung-XP941-512GB-PCIe-MZHPU512HCGL/dp/B00JOSM3TK

>I unfortunately have the 840 in this PC but I run linux, so their fix isn't 
>so handy.

  Bet they are still faster than the Corsair and other counterparts from
the same mfg era.

On 2014-11-02, Joerg <news@analogconsultants.com> wrote:

> Only question is, how can one connect two regular OPC monitors to this?
>
> http://www.geforce.com/hardware/desktop-gpus/geforce-gt-720/product-images

Assuming you consider VGA to be irregular use a HDMI to DVI cable for
the other,

-- 
umop apisdn

On 2014-11-03, rickman <gnuarm@gmail.com> wrote:
> On 11/2/2014 5:28 PM, Jeff Liebermann wrote:
>> On Sun, 02 Nov 2014 14:56:04 -0500, rickman <gnuarm@gmail.com> wrote:
>>
>>>>> One catch.  LTspice saves its preferences to:
>>>>>     C:\windows\scad3.ini
>>>>> which has to be writeable.  The fix is to use the
>>>>>     -ini <path>
>>>>> command line switch, which will:
>>>>>     Specify an .ini file to use other than %WINDIR%\scad3.ini
>>>>> <http://ltwiki.org/LTspiceHelp/LTspiceHelp/Command_Line_Switches.htm>
>>
>>> I need to note this somewhere.  Writing to the Windows directory is a
>>> *very* bad idea.
>>
>> It was standard procedure in Windoze 3.1, where almost all
>> applications dropped pick_a_name.ini files in the C:\Windows\
>> directory.
>
> Yes, and Windows 3.1 crashed on a regular basis for about any reason 
> whatsoever just like 95, 98 and ME.
>
> MS has been telling developers since Win2000 and maybe since NT to not 
> put data files in the Windows or Program Files directories.  Many chose 
> to ignore this which wasn't enforced until Vista and became one of the 
> things everyone loves to hate about Vista.

? AFAIK Microsoft software is still putting data files there.


-- 
umop apisdn