2 Cores or 4 Cores, that is the question

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I am searching for a new laptop and my main requirement is that it run SSDR as well as practical.  From my study of previous posts here, I came to the conclusion that I should get an Intel i7 or equivalent processor. 

I was in Fry's Electronics near Portland Oregon and was asked if I wanted the latest i7 (5th Generation) or the older 4th generation.  I asked what the differences were.  I assumed they were all four core chips;  Wrong! According to the fellows at Fry's the newer 5th gen chips are all duo cores whereas the 4th were four cores.  I expect to get 16 GB of RAM and a separate GPU with at least 2 GB of memory.

As I understood from my earlier reading, a four core chip was recommended over a duo core.  Now I am trying to separate fact from opinion before making a $1500 laptop decision.  Will it really make any difference?  I understand SSDR is set up for Hyper-threading but I don't know whether it would benefit from twice as many cores.

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K4SC

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Posted 3 years ago

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John n0snx

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I was running a 5yr old i7 and it worked great
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Walt - KZ1F

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No, SSDR is not set up for hyperthreading.Hyperthreading is a chip technology that overlaps processing somewhat.

SSDR had essentially 4 primary distinct areas of execution. If this is strictly for SSDR a fast duocore will suffice. If you are going to run skimmer and dm-780 and this and that, get the quad core. I am surprised they still sell1 duo core. Forget about hyperthreading. An I5 is quad core with no hyperthreading. A fast I5 will be more than sufficient. Quad core is different than hyperthreading. I5 and I7 are both quad core, only I7 supports hyperthreading, of those two. If the difference is $1500, go with the I5.
(Edited)
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DrTeeth

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Walt, can the software tell the difference between a proper core and a hyper-threaded bluff one? You inferred that it can "SSDR is not set up for hyperthreading". IIRC, a threaded application cannot - a single core with hyper-threading will be seen as two cores to multi-threaded software.
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Walt - KZ1F

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No, to the software, the I7 looks like an 8 processor chip. Someone said Intel has I7 chips with 6 cores (12 if you count hyperthreading) I am referring to the 4 real core variety. A 4 real core hyperthreaded chip is, in actuality, closer to a 5-6 processor chip. Any given application, of which SSDR is one, just sees there are 8 processors when, in fact, there are not. WIndows, Linux, it looks like 8 processors. Saying SSDR is not set up for hyperthreading (I was on a tablet at the time) is not an indictment of SSDR, it just sees 8 processors and, it really likely never uses over 4 (likely 2 or 3). Yes, there are perhaps, now, 12 threads running, something in that vicinity, however. IO is incredibly slow compared to cpu so while there is a dedicated 'thread' to handle IO, it only needs a very small fraction of a cpu so the rest of the, what might have been it's time slice, can be spent on other things, more cpu bound things, other IO events.

On the one extreme, if an application were finding all prime numbers from 1 to infinity and that work was split between 4 processors or programming threads, yes, all 4 processors would show busy, on an I7 all 8 would show busy. However, it another program was simply processing IO, no processing, all 4 or all 8 processors would show idle. SSDR is IO bound. It can not display waterfalls or spectrums faster than the data arrives and the time it takes to display the data (that has arrived) is way smaller than the delay waiting for the next bit of data.  So, if you have a quad core I5 running all slices or panadapters, and running 30% CPU, you are using less than half your CPU capacity.

From a programmatic perspective, so long as you always have an available processor when a task comes to a ready state, you can't go faster than that. More cores will not make the program run faster. Faster cores will make the program run faster so long as there is something to do. If all threads are waiting for IO to arrive, more cores will not make the network run faster. You've past the point of diminishing returns.

I believe the duo core chips are actually dyadic chips, two real processors.I could be wrong.

Think of the checkout line scenario. If the person at the register can clear a customer before the next one arrives, there is little point to opening up a second register. It is only if people start backing up waiting for the clerk at register 1 to clear a customer that opening a second register is justified. Virtually anything that happens in SSDR is a direct result of an IO packet arriving. Yes, in geologic time (compared to the cpu processing rate) does a user's clicking on a band or ant or freq digit occur. That is like glacially slow in cpu terms.

A user has an I5 running SSDR behind a 6700 and is running at 50%. An I7 will not help him (her). Some software will report that as 200% cpu vs 400% cpu on an I5 or 200% vs 800% cpu on a 4 core I7.  So long as you always have an available processor, more available processors will not speed things up.

Having said all that, go with an I5. Don't pay extra for the I7....unless you are simultaneously doing a lot of other CPU bound stuff. Remember too, now-a-days the real graphically intensive stuff is done on the video card. Memory cards are cheap, get 8GB of memory. CPU's are not so cheap, get an I5 unless you can really justify paying the difference for another (functionally equivalent of ) 2 processors. If you are running a lot of virtual machines, yes, those faux processors are important. That is a different conversation though.
(Edited)
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Larry - W8LLL

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Here is a comparison for you, I am running a dell precision M4800 mobile workstation that  is a quad core i5 running at 2.80Ghz, 8 gigs memory and NVidia quadro k1100m 1 gig video adapter and it runs  very smooth Remote with softether vpn.

My home pc's  are Dell T7500 precision workstations running dual 6 core processors @ 2.68 Ghz  and  32  gigs of memory, that's 12 cores and to be honest the M4800 runs ssdr just as smooth.


The last few years I have  been running returned lease dell business class workstations that are only 2 years old when they are turned back in and auctioned/resold at 1/4 the original price, a lot of bang for the buck.

(Edited)
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Lee, Elmer

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It primarily matters what other software you want to run simultaneously and if you are running your video off the CPU or off a separate video card.  I've gone from a i3 to a i5 to a i7 as the complexity of the software I use increases.  SSDR over the past year has become dramatically more efficient so my i3 computer which I use remote with DDUTIL and a logging program runs in the 30% CPU usage range.  My i7 computer with multiple slices and multiple CW skimmers and logging software with multiple cluster connections runs 40% usage both running 2 HDMI monitors off the onboard chip video.  with only SSDR running the i3 runs 15% and the i7 about 9%.  Both chips throttle back to around 1.5ghz speed.  Since you are talking about a laptop I would go with the i7
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K4SC

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Thank you for the input.  I now know that Hyper-Threading is not the same as multi-threading.  Ended up buying an ASUS G751 laptop that has the i7, 16 GB Ram expandable to 32 GB, a 1TB HDD with an open bay to add another SSD, and a 3GB Video Card.  I think that will probably do the trick. 

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Jay / NO5J

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Does it have 2 or 4 cores? 
73, Jay - NO5J
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K4SC

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The i7 in my new ASUS is the 4th generation 4 core version; the newer 5th generation i7 chips have only 2 cores, so I'm told by the people at Fry's.
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Jay / NO5J

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By 5th generation I assume they meant 14nm chips, so far Intel hasn't released anything but 2 core mobile chips at 14nm. The 14nm desktop chips with 4 cores, began being released this month. I suspect there may be some 4 core 14nm mobile chips,later on. It's just too early in the release cycle I guess. the 4 core, 4th generation 22nm you purchased will likely out perform the new2 core chips, so you made the right decision.

73, Jay - NO5J