Is this Intel i7 machine good for LTSpice?

That sounds like a high-testosterone machine of a computer :-)

Which processors is in there?

I've read that many DOS and also Windows 16-bit programs no longer run.

Yep. And all I have to try is LTSpice, the rest will work.

I never had that happen. Plus the SW I run is mostly not mainstream and should be very low on the hit list of hackers.

You aren't grasping the concept. Video memory needs a sizable bandwidth to *display* the image to the screen. All the data that goes out over your HDMI cable is being read from memory *all the time*. You're a bright boy. Do the math... 1920*1080*60 times 3 or 4 bytes per pixel.

This has *nothing* to do with drawing the images into graphic memory.

The memory bank question will likely be more important than the number of cores in the CPU. The guy who can run 16 threads has at least two memory interfaces or it would be bogging down between 4 and 8 cores.

That kind of stuff cinches it for me: It has to be Win-7.

On Mon, 03 Nov 2014 16:01:39 -0500, rickman Gave us:

So, you really know nothing about actual attachment to real hardware hooks then, eh, dingledorf?

You ain't real bright, boy.

with anything but a graphics-card integrated in the chipset that memory will be on the card itself, 1920*1080*24bit is less that 7MB

-Lasse

Maybe. But for us users only one thing counts: That stuff works.

If it was allowed in old Windows, isn't in new Windows, and there isn't a user selector about this then I blame Windows.

Easy to say for someone who probably never has to deal with beamfield sims and such. Bottomline there are programs some of us have to use where there is no alternative. Where the design teams have dissolved decades ago and some of the folks are not with us on earth anymore. My record so far is a chunk of software that was stored on an 8" floppy.

Software does not automatically lose its value because it is over 20 years old. Or would you pour a bottle of 1995 Domaine Leflaive Montrachet Grand Cru [*] into the sink because it is old?

Talking about using legacy stuff, the aircraft guys are a bit more extreme there. This aircraft is going to celebrate its 80th soon and is used commercially:

Well ... we did enter the 21st century. In this day and age graphics cards come with their own memory. AFAIK the Nvidia GT720 has 1GB of on board RAM. Others have more but that sounds sufficient. Also, there is no need to store 60 frames if the content is more or less static.

If you can persuade them to do it a gamer machine with the graphics card entirely deleted will be the cheapest low power combo to do about what you want. The 2D capability of the Intel graphics engine internal on the i5 & i7 CPUs are as fast as anything on fancy 3D gaming cards. (obviously they get totally thrashed in 3D realtime rendering tests)

Basically you can shave 100-200W of the power consumption. My i7 PC idles at about 60W when it isn't doing anything beyond web browsing.

BTW I wouldn't waste your money on exotic faster ram unless you intend to overclock it. Stock ram and more of it is a better price performance.

I'd be interested to see how a moderate sized LTSPice simulation scales with the number of threads on an i5 and i7 architecture. My guess is that hyperthreading will not be all that useful to it.

Problem is, unless you piece together a custom machine the ones that are equipped with good processors and RAM up to the gills seem to always come with these powerful graphics cards. The other issue is that on-board graphics often will not drive two monitors. I found that out the hard way after I bought the PC I am using now.

So you think 1600MHz RAM is fine?

I am hoping the four cores will speed things up significantly. Also the huge amount of RAM. Right now I have 2GB and I regularly hit the limit.

how do you figure that ? As far as I know, most video cards map a whole 32 bit per pixel for 24bit (true color) these days.

That would equate to somewhere around 67 megs I do think.

I don't know, maybe there is some compression magic I don't know about..

Jamie

Do you build your stuff so that if the user connects a different computer it craps out? No, you design your interfaces *correctly* so that it works now and it keeps working when some peripheral piece that should have no impact is changed out.

These developers are designing crappy software and blaming it on MS.

"Allowed" meaning it didn't crap out, yes. "Allowed" meaning the developers were not designing according to best practices, no.

Yeah, exactly. If you are that far back in time you man need to rethink your approach.

Actually software does degrade with time as you are finding out. If you can't find a platform to run it on, it has worn out.

Good, maybe your beamfield sim will run on it. :)

It is not the amount of memory, it is the video bandwidth to keep the monitor refreshed. Yes, it should be separate from the main memory or you take a hit from the video accesses.

That's megabits. In bytes this would be 8.3MB. Times two if there's two displays. With the massive quantity of onboard memory on modern graphics cards that is a mere drop in the bucket.

No need for compression.

I don't know if you are playing with me or what. Yes, that is what I am telling you, get a system with separate graphic memory which means a separate graphics chip. Many mobos have built in video with *no* video ram.

It has a pair of AMD Opteron 6128s. I haven't been keeping up, but 3 years ago the Magny Cours Opterons ran rings around the Intel offerings for floating point.

Cheers

Phil Hobbs

It has a pair of AMD Opteron 6128s. I haven't been keeping up, but 3 years ago the Magny Cours Opterons ran rings around the Intel offerings for floating point.

Cheers

Phil Hobbs

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I design it so that is also works correctly with legacy gear. In aerospace that can mean equipment from before you and I were born.

I've underlined the important part above. You might remember that there were operating systems before Win2k and that there was software written for those.

If it was not disallowed it was ok. Even today it's still this way. Personally I also think it was wrong but it is what it is. Many CAD programs still store their libraries in the program folder and, naturally, libraries are meant to be modified and added to.

Any suggestions there? Should I tell my clients that this, that and the other project can't be done because only older design tools are available?

Imagine you having a leak in the house. The plumber comes, takes a look and says "That wouldn't be up to code these days although it was back then. I suggest you build a new house and have this one torn down".

My software does not run out. My hardware does. I get more and more into pulse-echo stuff and esoteric switch mode designs where the amount of data to be crunched overwhelms the machine.

BTW, when the in-circuit tester at one client conked out the culprit was the PC. Had an ISA bus. It was no problem to buy a brand-new machine at a very reasonable price that has an ISA bus. Except now they also have a CD drive in it.

:-)

Example from a few years ago: A nasty alarm system problem had to be diagnosed. The software from that system was from the 80's. If I hadn't been able to run it really old software here at my lab I would have had to turn down that whole job. That would not be what I call smart.

even so, unless you play 3D games that need massive amount of texture memory I doubt it matters much

an I7 have something like +30GByte/sec memory BW depending on memory config

refreshing two full HD monitors at 60Hz is only a few percent of that

-Lasse