Hyperthreading

[moonbounce]

I am looking to buy a computer, I have two in mind. The first computer is a desktop with Intel i5 2500 cpu, the second is a laptop with an intel i7 620m cpu, My question is which is faster at processing multi threaded applications the i5 2500 @ 3.2 GB or the i7 6200m at 2.66 GB with hyperthreading?

I have read a lot of information on this subject but I guess I just need a simple explanation as I still don't understand,

Thanks
Moonbounce
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[muchomorek]

Intel Core i7 620M vs i5 2500

 

[moonbounce]

Intel Core i7 620M vs i5 2500

Which would bring me back to my question about hyperthreading with a low speed processor vs high speed non hyperthreaded cpu in actual using which is better?
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[corbintechboy]

Which would bring me back to my question about hyperthreading with a low speed processor vs high speed non hyperthreaded cpu in actual using which is better?
.

Hyper threading would allow you run more tasks at the same time where a higher clock speed would give you a faster response time.

I have an i7-4810m in my laptop. It is fast and it takes a lot for me to choke the cpu. I can choke it with to many compile jobs in Linux, in day to day use however, I cannot choke it.

To break this down in a simple manner, think like this.

None hyper threading:

--data---[core]------> Single pipe.

Hyper threading:

--data---|core|----->
--data---|core|-----> (this is a single core)

Simple break down.

 

[corbintechboy]

Hyper threading would allow you run more tasks at the same time where a higher clock speed would give you a faster response time.

I have an i7-4810m in my laptop. It is fast and it takes a lot for me to choke the cpu. I can choke it with to many compile jobs in Linux, in day to day use however, I cannot choke it.

To break this down in a simple manner, think like this.

None hyper threading:

--data---[core]------> Single pipe.

Hyper threading:

--data---|core|----->
--data---|core|-----> (this is a single core)

Simple break down.

EDIT: Just to add my opinion, i7 is a better CPU (even though the one you posted is old). It is more future proof and your biggest speed increase will come from an SSD. So any speed you will gain from the faster clock speed will not really be noticed in the machine if equipped with an SSD.

(this was not supposed to be a double post. I think I hit the wrong button )

 

[questnz]

Also check here for you reference: just pick your CPU preference
Gaming CPU Performance - Hierarchy Chart - Intel vs. AMD
CPU Benchmarks - Compare Products on AnandTech

 

[CapStar362]

hyperthreading in general allows two threads per core to be executed.

by "threading" the data as one stream per say to each core.


to the standard user looking at Task Manager, they see 8 cores as the OS see's it that way, you still have only 4 ( for a quad ), but the HT paths, logically count for 2 cores per HT Path because its allowing 2 data threads per core.

in simplistic terms,

take two strings, twist them together, run them down a single pipe.

Hyper Threading

without HT, it would be:

two strings and two pipes running together.


Here is a VERY simple diagram for HT:

http://www.dasher.com/wp-content/uploads/2015/02/Intel-HT.gif

 

[br0adband]

Hyperthreading aka HT doesn't actually give you the performance of a quad core if you happen to have a dual core w/HT enabled (2 cores/4 threads). What hyperthreaiding does is provide additional computing power in a limited manner to get tasks done. In a typical scenario if you have a dual core processor (or a dual core w/HT support but the hyperthreading is disabled so only two threads are functional) and you do a task that's multithreaded you'll get a specific level of performance. With hyperthreading enabled on that same CPU (so now it's 4 threads) it doesn't mean double the performance aka 2 vs 4. It's just a small boost in the long run so here's an example:

Say you have something like a Core i5-2540M CPU which is what I have in my laptop currently. It does support HT so in Task Manager what I see (when I enable the ability to see the logical cores or one graph per CPU) is "4 cores" basically. Now, if I were to disable the HT side of things and then run a multithreaded benchmark that tests the CPU's processing capability alone (not a RAM test or GPU, strictly CPU bound test) I'd get a level of performance.

Now if I enable HT on this processor (in this example) and then re-run the same benchmark it'll now have 4 threads to run - but the issue is those additional threads aren't going to provide the same level of processing capability the actual physical processor cores do. Hyperthreading typically gives a 15-20% boost on average (with up to roughly 30% max depending on the code) to overall performance, so again with specific numbers it's something like this:

With HT disabled if I get a score of 100 on the multithreaded benchmark (it's an arbitrary number just for this example) I would expect to see a score of about 115-120 (or close to it) if I enable the HT for the additional threads.

Marketing gimmicks and general consumer ignorance about what HT actually is and what kind of performance benefits you get leads most consumers to see something like "2 cores 4 threads" and think that it means it'll work like a quad core instead of a dual, or a quad core with HT having 4 cores and 8 threads being even more (which it is because it's twice the physical cores primarily).

So basically in the long run a dual core with HT (2 cores/4 threads) will perform better than a plain old dual core or that CPU with HT disabled, but a 2 core/4 thread processor vs a true 4 physical core processor without HT = the true quad core would perform better. Per the example numbers above:

2 cores/4 threads = 115-120 on that benchmark
4 cores/8 threads = 230-240 on that benchmark

Because the quad literally does have more physical cores which do full processing then yes, the performance literally doubles on properly multithreaded code and the HT support bumps that 15-20% more on average.

In the OP's case, the i7 laptop processor vs the desktop i5, that i5 will tear the i7 apart because they're two very different architectures overall (laptop vs desktop) but also because the i5 has other aspects that improve on the i7 (that's a 1st gen i7 laptop CPU and a 2nd gen desktop i5).

Nuts and bolts, the CPUBoss comparison above is a valid one, obviously, and the numbers for the i5 thoroughly trounce the i7. The i7 would be somewhat smoother operation overall if you're a heavy multitasker, but when it comes down to straight pure multithreaded performance, the difference in clock speed and the other improvements with the i5 make it the winner in that comparison. Hyperthreading helps, but it doesn't double the processing performance when executing multithreaded code, it just gives a small bump of roughly 15-20% but every little bit matters.

Hope this helps...

And an even more wordy technical explanation:

http://www.dasher.com/will-hyper-threading-improve-processing-performance/

 

[CapStar362]

well don't know what to say other than i said "logically" the OS see's 8 CPU's, not physically.

can't argue with the OS itself, which i have a 3770K with HT. and what is Win 8.1 reporting here in the image?

4 Physical and 8 Logical. Cores in Red and Logical Cores in Blue.


i can disable my HT and show you another image with 4 Cores and 4 Threads if you would like?


the 8 Logical is because the HT makes the OS "think" one HT link is two cores. it allows two threads to be executed per HT Link.


this is how i was taught and this is how Intel/AMD and MS implement it. i never said it actually gives a Dual core, a QUAD core in physical terms, it simply threads two threaded sets of code into one, and executes them simultaneously per processor scheduling, which in turn for multimedia and especially gaming terms... is a nice boost. for most single threaded applications, its a marginal if minimal boost at best.


Go back to the Pentium 4 days, when HT first came out. why did XP suddenly start displaying on its Task Manager or hell, even back with the OS Being Win 2k, when implemented the right way with a P4 with HT.

why all of a sudden, does 2 CPU's get reported?

Because HT makes the OS Think there actually IS two CPU's when its physically one, but two threads are present logically.

 

[CapStar362]

and here is HT Disabled. like i said, 4 Cores 4 Threads

 

[CapStar362]

worthy of noting. just the OS boot time between HT Off and HT On, almost 7 seconds difference. and this is a SSD as a boot drive.


Architecture wise, no contest between a older i7 and a 2nd gen i5. far more optimized.


but for the sake of the HT Argument, its logically presented to the OS As 8 CPU's, because the way HT Works the OS "thinks" there is that many CPU Cores present.


I had a old HP Server once, a Quad Socket 604 Xeon Setup. want to take a guess how many CPU's 2K Server was displaying?

8 CPU's were being reported, as these where the first of the Xeon Skt 604s ( Prestonia Core ) with HT. 2 per physical CPU Socket.

 

[moonbounce]

Thanks everyone for taking the time to clarify this very confusing topic. I was trying to figure out which was faster at processing a multi threaded application a fastercpu or a slower cpu with hyperthreading

From what I have read over the last day or so the actual multi threaded program has a big play in what happens when the multi threaded app. hits the cpu along with the I/O devices. A very confusing topic for the general computer buying population of which I am one.

I think I will be going with the desktop with the i5 2500, again thank you all very much.

Moonbounce

 

[br0adband]

As the i5 2500 is still a fantastic processor it's worthy of owning if you're not a massively hardcore computer power user - having said that, the one piece of advice I will offer is that because of the age of the processor and whatever else happens to be in whatever computer you're looking to buy or build (RAM, storage, video, case, power supply, sound card, everything that comes with a desktop up to and including keyboard/mouse/monitor/etc), don't spend a lot of cash for such a machine. Even in spite of the i5-2500 being a great CPU even today, I wouldn't spend more than $200-250 for a desktop with that CPU in it at this point in time, and at the price range it would need to have 4-8GB of RAM, at least a terabyte of hard drive storage (I doubt it would have an SSD if you're buying used but it might, I can't say for certain), and a decent good condition case with a name brand motherboard from Asus, Gigabyte, Asrock, or even pure Intel if that's what it has.

Basically, the i5-2500 will be the core of an older complete working computer system (my guess) so don't let a potential seller take advantage of you just because you may not be as intimately aware of the hardware ins and outs like some of us hardware geeks happen to be.

If you're buying used, check out the system as thoroughly as you're able - if you have a friend in your area that's more knowledgeable about computer hardware and systems, ask if he/she can take a look with you and determine if the system is worthy of the cost being asked, and then negotiate from there if the friend says it's worth considering at <whatever cost>.

If you're buying a prebuilt system someone might be putting together for you, like a local PC shop or something, then again, be wary of pricing for older hardware which would probably make up the bulk of such a machine based on the i5-2500. In your original post you mentioned a desktop computer with the i5-2500 so again I'd say $200-250 depending on condition and included hardware - an i7-620M laptop at this point in time would probably go for $175-225 or something close to it, again the price depends not only the CPU but the supporting hardware (RAM/storage/video/etc) - the actual CPU is just a part of the big equation so factor that into the complete pricing.

Hope this helps as well...

 

[CapStar362]

^ ^^ THIS

i would have someone check it with hardware checking software. make sure it passes a MEMTest+ at least one full pass, and any other hardware testing this person has. and VERIFY it with a screenshot or external photo of the screen.

there is no telling how long these parts have been in use. most people just throw power and say: ok it boots, its good. when it quite usually is the opposite. it may perform basic POST and boot function, but once it gets up to operating temps and into more complex functions, errors start occurring and failures start dropping.

cant tell you the number of people i have worked systems with this particular case set.

 

[moonbounce]

I just happened to read BroadBands last comment and I decided to leave that computer alone and find something newer. The computer was an HP Compaq 8200 Elite with the Intel i5 2500 for $300. It was being sold by a company that is pretty reputable ( I bought the computer I am typing on from them only it was brand new ) the computer was an off lease type and they put a fresh copy of Windows 7 on it and gave a 90 warranty.

So I am going to look for a laptop instead of a desktop so any hints at a good laptop around $ 300? It seems like used laptops or desktop computers are hard to come by in my neck of the woods, don't know if it is just the time of year or what, but I will keep looking.

Thanks again for all the replies,

 

[br0adband]

Was going to do this really long complicated very detailed post of info but that's overkill so I'll simplify it a bit.

If you can buy something from eBay Canada, it's worth checking into. My recommendation is to look for business class hardware from HP or Dell like HP Elitebook laptops or EliteDesk desktops or Dell Latitude laptops or Precision desktops. I don't recommend consumer class hardware, haven't in a few decades and I see no reason to alter that stance.

Also, only deal with sellers (individuals or companies) that have a 95%+ positive feedback or better, that offer actual return policies of some kind (even if it's just 14 days that's better than some sellers who don't offer anything at all so read the fine print on every item page, top to bottom, carefully).

Right now one of the most popular series of laptops in the used market are the HP Elitebooks and the Dell Latitudes, especially the Latitude E6420/E6430/etc series. The models you'd find on eBay Canada would be ones from companies that had huge fleets of these kinds of laptops, which are business class machines with magnesium or aluminum bodies and chassis and are rock solid hardware. When companies upgrade their fleets that do it thousands of laptops at a time so other companies buy up their entire fleets for a lump sum price and then offload them (after some reconditioning if needed) on eBay Canada (and here in the US obviously, I just say Canada since that appears to be where you're located).

I just realized when I was quoting the price ranges in my post above that I didn't take that into consideration - I was quoting prices in US dollars so I suppose if you adjust that accordingly (give or take $25-50) then it'll be in the ballpark.

As for in your neck of the woods, I just looked at the London Ontario CA listings for craigslist and, wow, you weren't kidding: there's only like 8 computers listed in the owner's category. Just for comparison, the Las Vegas listing for the owner's category gets 8 computers listed every hour... geez, what a difference.

Final word (Disclaimer - the following is personal opinion only and should be taken as such):

Avoid HP Pavilion laptops if you can in all respects, just run in the opposite direction of 'em. I am speaking only for myself here, but after working on computers since the 1970s, that is the single most horrendously terrible series of laptop products I've ever encountered in all of those years. I've repaired a few hundred of them and I'm sick of dealing with that crap hardware. Case in point: the entire dv series from years ago in the 2000/4000/6000/8000/9000 series with Nvidia GPUs on them were defective, every last one of them. Now, while the consumer owning one of those models might not directly experience problems that doesn't dismiss the fact that they were all shipped from the factory with substandard solder which caused GPU failures over time and rendered the machines basically useless. Most of those models were made 8-9 years ago so they still exist in the used computer market.

The newer Pavilion dv series machines like the dv5, dv6, etc, are somewhat better but I am ruined for Pavilion hardware, period, and so I will recommend them to be avoided at all costs.

They are the one particular line of computers I simply won't touch anymore, even for repair jobs, I just won't do it. HP EliteBook laptops (and ProBooks) are damned nice hardware, however.

Typical used pricing for such business class laptops made in the past 5 years are roughly $250-325 and that's Canadian dollars. I'm looking at the ebay.ca site right now and see a bunch of Dell Latitudes in that range which are rock solid machines. One thing to take note of is if you intend to play games - I have no idea if you will or not so I'm presenting the info - is that most of these business class laptops have the Intel GPUs (the HD 3000 or HD 4000 onboard graphics because they're part of the chipset/CPU). If you look for one that has an Nvidia GPU (for Dell Latitudes) or an ATI/AMD GPU (for HP EliteBooks) that will give you much better graphics performance that can play some games with medium graphics settings.

If you're a hardcore gamer then such laptops aren't going to cut it but then again for such gaming oriented machines the prices will be higher to begin with.

I could go on for hours with recommendations but the best thing overall is make sure you're buying from a reputable seller and read all the fine print in the ads, top to bottom, the whole page. If you do choose something local, the advice I presented above about checking it out prior to handing over the cash for the purchase is still recommended.

Good luck...

 

[moonbounce]

Thanks BroadBand, if you think 8 computers on Craig's list is bad you should try Kajiji for London ont it is even worse. I may have to wait until the fall to find a decent laptop. Thanks again for your help I will totally leave P alone. Is that the same for their desktops?

I don't really play games, I am mostly into DSD and SDR stuff and playing the odd video here and there. I am just looking to get a more powerful laptop, an I5 or I7. There is a Lenovo Thinkpad T420 with the Intel i5 2520m 4 GB of ram that I am going to go look at. I am also kinda partial to Lenovo.

Agian thanks for the input, and the HP warnimg.

Moonbounce

 

[br0adband]

The HP Pavilion desktops are just "meh" in my opinion, there are better pieces of hardware out there. Again, it's that consumer vs business class concept - it's nice to see you're looking at ThinkPads in the T-series because they're great hardware. I will say that started with the T430 I was and am disappointed with what Lenovo is doing with the long-standing ThinkPad reputation which is making too many changes that many of us diehard ThinkPad fans and owners have come to appreciate. I've owned many ThinkPads over the decades from the original 700c to the famous 701c "Butterfly" model and a lot of others along the way and there's a certain appeal to the flat black styling with the red and blue accents they've always had.

Having said that, the ThinkPad "Edge" series of laptops is more what would be considered a consumer class laptop by Lenovo that takes cues from the actual ThinkPad business class line, but they are very different devices when it really gets down to it. The T-series along with the X-series of ThinkPads are the best sellers, business class top to bottom, with magnesium chassis components and mid to high end hardware filling them out so they are most definitely worthy of consideration.

The T420 is a nice device and with the i5-2520m and 4GB would be a rock solid device for years to come, it's comparable to the Latitude E6420 I own presently (I have an i5-2540m so basically the same CPU just a nudge faster on the clockspeed). If you can check that machine out, and it's in great shape overall and the price is right, grab it and you'll be happy you did, at least that's the hope.