Forums

LTspice Loafing?

Started by rickman March 9, 2017
I was running some simulations on LTspice and it is not even using 5% of 
my CPU.  Nothing else is topping it and the entire computer is pretty 
much at idle.  What could be limiting the speed?

One of the main reasons I bought a laptop with an i7 processor was to 
speed simulations.  Is this wasted on LTspice or am I doing something 
wrong?

-- 

Rick C
On 03/09/2017 09:29 AM, rickman wrote:
> I was running some simulations on LTspice and it is not even using 5% of my CPU. Nothing else is topping it and the entire computer is pretty much at idle. What could be limiting the speed? > > One of the main reasons I bought a laptop with an i7 processor was to speed simulations. Is this wasted on LTspice or am I doing something wrong? >
I think it saves the waveforms to a file as it goes along simulating. Where you the one who complained about your hdd being slow in an earlier thread? maybe try running the sim from an ext usb stick. if that helps it's definitely the hdd.
On Thursday, March 9, 2017 at 7:29:17 PM UTC+11, rickman wrote:
> I was running some simulations on LTspice and it is not even using 5% of > my CPU. Nothing else is topping it and the entire computer is pretty > much at idle. What could be limiting the speed? > > One of the main reasons I bought a laptop with an i7 processor was to > speed simulations. Is this wasted on LTspice or am I doing something > wrong?
It might be worth buying more RAM or a solid state hard disk. LTSpice can get very slow when the waveform files are are being swapped out of RAM onto hard disk. -- Bill Sloman, Sydney
On 03/09/2017 05:37 AM, Johann Klammer wrote:
> On 03/09/2017 09:29 AM, rickman wrote: >> I was running some simulations on LTspice and it is not even using >> 5% of my CPU. Nothing else is topping it and the entire computer >> is pretty much at idle. What could be limiting the speed? >> >> One of the main reasons I bought a laptop with an i7 processor was >> to speed simulations. Is this wasted on LTspice or am I doing >> something wrong? >> > I think it saves the waveforms to a file as it goes along > simulating. Where you the one who complained about your hdd being > slow in an earlier thread? maybe try running the sim from an ext usb > stick. if that helps it's definitely the hdd. >
I'd start with a ramdisk and see then. USB sticks are glacial compared with real flash drives. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
> >> I was running some simulations on LTspice and it is not even using > >> 5% of my CPU. Nothing else is topping it and the entire computer > >> is pretty much at idle. What could be limiting the speed?
Make sure the hard drives are running in DMA mode not PIO mode. They automatically and permanently fall back to PIO mode if there are hardware errors. mark
On Thu, 9 Mar 2017 09:53:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 03/09/2017 05:37 AM, Johann Klammer wrote: >> On 03/09/2017 09:29 AM, rickman wrote: >>> I was running some simulations on LTspice and it is not even using >>> 5% of my CPU. Nothing else is topping it and the entire computer >>> is pretty much at idle. What could be limiting the speed? >>> >>> One of the main reasons I bought a laptop with an i7 processor was >>> to speed simulations. Is this wasted on LTspice or am I doing >>> something wrong? >>> >> I think it saves the waveforms to a file as it goes along >> simulating. Where you the one who complained about your hdd being >> slow in an earlier thread? maybe try running the sim from an ext usb >> stick. if that helps it's definitely the hdd. >> > >I'd start with a ramdisk and see then. USB sticks are glacial compared >with real flash drives. > >Cheers > >Phil Hobbs
Isn't there a way to save fewer nodes? -- John Larkin Highland Technology, Inc lunatic fringe electronics
On 3/9/2017 5:37 AM, Johann Klammer wrote:
> On 03/09/2017 09:29 AM, rickman wrote: >> I was running some simulations on LTspice and it is not even using 5% of my CPU. Nothing else is topping it and the entire computer is pretty much at idle. What could be limiting the speed? >> >> One of the main reasons I bought a laptop with an i7 processor was to speed simulations. Is this wasted on LTspice or am I doing something wrong? >> > I think it saves the waveforms to a file as it goes along simulating. > Where you the one who complained about your hdd being slow in an earlier thread? > maybe try running the sim from an ext usb stick. if that helps it's definitely the hdd.
NONE of the computer features I can see in Task Manager are being taxed at all. The disk is near zero utilization and there are 2 GB of free memory. I just watched and LTspice was only using 5% of the CPU. -- Rick C
On Thu, 9 Mar 2017 09:53:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 03/09/2017 05:37 AM, Johann Klammer wrote: >> On 03/09/2017 09:29 AM, rickman wrote: >>> I was running some simulations on LTspice and it is not even using >>> 5% of my CPU. Nothing else is topping it and the entire computer >>> is pretty much at idle. What could be limiting the speed? >>> >>> One of the main reasons I bought a laptop with an i7 processor was >>> to speed simulations. Is this wasted on LTspice or am I doing >>> something wrong? >>> >> I think it saves the waveforms to a file as it goes along >> simulating. Where you the one who complained about your hdd being >> slow in an earlier thread? maybe try running the sim from an ext usb >> stick. if that helps it's definitely the hdd. >> > >I'd start with a ramdisk and see then. USB sticks are glacial compared >with real flash drives. > >Cheers > >Phil Hobbs
Try this one. 32 seconds on my new Dell. Runs about 25% CPU. Version 4 SHEET 1 880 680 WIRE 16 -16 -160 -16 WIRE 208 -16 16 -16 WIRE 336 -16 208 -16 WIRE 208 48 208 -16 WIRE 336 48 336 -16 WIRE -160 144 -160 -16 WIRE 16 144 16 -16 WIRE 208 192 208 128 WIRE 336 192 336 112 WIRE 336 192 208 192 WIRE 208 256 208 192 WIRE 16 304 16 224 WIRE 144 304 16 304 WIRE -160 352 -160 224 WIRE 16 400 16 304 WIRE 208 400 208 352 WIRE 16 544 16 464 WIRE 208 544 208 480 FLAG 208 544 0 FLAG 16 544 0 FLAG -160 352 0 SYMBOL ind2 192 32 R0 WINDOW 0 -50 31 Left 2 WINDOW 3 -54 69 Left 2 SYMATTR InstName L1 SYMATTR Value 1m SYMATTR Type ind SYMBOL ind2 224 496 R180 WINDOW 0 -54 75 Left 2 WINDOW 3 -63 38 Left 2 SYMATTR InstName L2 SYMATTR Value 20&#2013266101; SYMATTR Type ind SYMBOL cap 320 48 R0 WINDOW 0 63 12 Left 2 WINDOW 3 59 51 Left 2 SYMATTR InstName C1 SYMATTR Value 50n SYMBOL cap 0 400 R0 WINDOW 0 61 10 Left 2 WINDOW 3 64 46 Left 2 SYMATTR InstName C2 SYMATTR Value 1&#2013266101; SYMBOL npn 144 256 R0 WINDOW 0 116 42 Left 2 WINDOW 3 92 77 Left 2 SYMATTR InstName Q1 SYMATTR Value BC847B SYMBOL res 0 128 R0 WINDOW 0 52 39 Left 2 WINDOW 3 49 75 Left 2 SYMATTR InstName R1 SYMATTR Value 20K SYMBOL voltage -160 128 R0 WINDOW 0 51 41 Left 2 WINDOW 3 50 75 Left 2 SYMATTR InstName V1 SYMATTR Value 10 TEXT 240 232 Left 2 !K L1 L2 0.98 TEXT -240 480 Left 2 !.tran 0 20m 0 10n uic TEXT 424 272 Left 2 ;LC Oscillator from C5A TEXT 416 312 Left 2 ;Boresight Alignment Kit TEXT 448 376 Left 2 ;JL roughly 1975 -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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>On Thursday, March 9, 2017 at 7:29:17 PM UTC+11, rickman wrote: >> I was running some simulations on LTspice and it is not even using 5% of >> my CPU. Nothing else is topping it and the entire computer is pretty >> much at idle. What could be limiting the speed? > >> One of the main reasons I bought a laptop with an i7 processor was to >> speed simulations. Is this wasted on LTspice or am I doing something >> wrong?
>It might be worth buying more RAM or a solid state hard disk.
>LTSpice can get very slow when the waveform files are are being swapped out >of RAM onto hard disk.
Yes. True for any spice. Once it starts memory swapping, its all over. Always get as much memory as you can if running spice. I've had 16 GB on my computers for many years now. -- Kevin Aylward http://www.anasoft.co.uk - SuperSpice http://www.kevinaylward.co.uk/ee/index.html
On 3/9/2017 1:33 PM, John Larkin wrote:
> On Thu, 9 Mar 2017 09:53:26 -0500, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 03/09/2017 05:37 AM, Johann Klammer wrote: >>> On 03/09/2017 09:29 AM, rickman wrote: >>>> I was running some simulations on LTspice and it is not even using >>>> 5% of my CPU. Nothing else is topping it and the entire computer >>>> is pretty much at idle. What could be limiting the speed? >>>> >>>> One of the main reasons I bought a laptop with an i7 processor was >>>> to speed simulations. Is this wasted on LTspice or am I doing >>>> something wrong? >>>> >>> I think it saves the waveforms to a file as it goes along >>> simulating. Where you the one who complained about your hdd being >>> slow in an earlier thread? maybe try running the sim from an ext usb >>> stick. if that helps it's definitely the hdd. >>> >> >> I'd start with a ramdisk and see then. USB sticks are glacial compared >> with real flash drives. >> >> Cheers >> >> Phil Hobbs > > Try this one. 32 seconds on my new Dell. Runs about 25% CPU.
Mine is an i7 and runs about 25% (only one core, apparently) and takes about 53 seconds. The computer is about 5 years old.