Hyperthreading/ Multicore & more in layman's terms...

[katzdvd]

I've heard all these terms over the last few years, & have checked out google, wikipedia, & others for the definitions & understanding, but I still come away a bit foggy;

Can I get a "simple" explanation??? Or, if there is a good website(s), that would be good. I can read the definitions, I just don't understand how it works in "real life" applications.

For example, with the multicore processors; What is this about bringing one core up at a time? How is this accomplished?

When (if) I build my next (multicore) system, I won't even know how to use it! Need it to be "dumbed down" a bit!

Signed; Thoroughly confused!

[UncasMS]

Put it simply: you won't have to do much to profit from multiple cores - the application (your favourite game, maybe photoshop or e.g. dvd rebuilder (PRO)) will have to take care that two or more cores are being used for whatever job will have to be done.

Let's take games for example:
"Crysis" is said to significantly gain from multicore environments by using the CryEngine2.
Crytek claims 98% gain in a quadcore system over a single core platform, which isn't bad at all after years of hardly any gaming benefit from dual or more cores.

Photoshop as the state-of-the-art image processing tool is said to take advantage of multicore cpus but bandwidth is the extremely limiting factor in PS as opposed to video processing and thus PS does not gain that much from 4 or even 8 cores but 2 cores made quite a difference for me compared to my previous single core.

using massive raw data from your camera and work with them still takes quite a while but more than 1gb ram and decent harddrives with ps swapfiles on them make a difference.

Video rendering or transcoding finally are the tools that profit massively from 2 or more cores.

Take dvd rebuilder pro for example: using encoders like HC or PROCODER you will end up with two instances of the encoder working on different segments of the movie, while cce itself cannot be started twice and thus there is only one instance of cce running but cce is highly optimized and uses most of the available cpu power.

HC and PROCODER now work almost at the same speed a single core platform would provide but they have TWO instances running parallel and thus they take much less time these days on dual cores - i can't judge what difference quadcores make (ipaulo might be the one to tell us)

And video rendering suites like MAYA are said to benefit from multicore platform very much as well, but i am not into this stuff so i can't tell.


last but not least a 64 bit OS like xp 64 is a good choice when it comes to multicore platforms!

[cynthia]

Do both cores run at the same speed as a single core processor would run at?

[UncasMS]

From memory (no scientific proof available) i'd say with equal core speeds the encoders run at ~90% of the speed of that of a single core but you know how hard it is to compare speeds.

i don't have my single core with 2400mhz at hand anymore and so it is not possible to start up the very same title (or otherwise we wouldn't even have to compare numbers) on a single and a dual core machine.
But the numbers i have in mind from single core encodings are similar to the numbers i see now for each of the two cores keeping the encoder busy.

could be interesting if anybody was able to run this kind of test!?

i don't think it makes sense to note down the times rebuilder will take with its two different options, which will make either one or all cores work: "multiple encoder processes" but even that might be worth posting some time soon in order to show the benefit of multicore processing.

[katzdvd]

Thanks for the info, UncasMS. That did make it a bit more plain to me. But, what about this?

For example, with the multicore processors; What is this about bringing one core up at a time? How is this accomplished?

I have seen that in posts on here before. Does this mean that the user is doing this? From what you posted, I understand the program that is used (Photoshop/game, etc.) does this on its' own?

[soup]

I have never had to do anything different than I used to do with single core, when it comes to running stuff, except when I have gotten a runtime exception error, when running a program. When that happens, you have to open the program, go in to Task Manager & set the Affinity to one core or the other not both. Maybe somebody can explain it a bit better.

[ipaulo]

I did a test with DvdRebuilder. I have 2 gigs of memory 1066 with everything at stock speed. Rebuilder is set at Low Priority and in movie only mode. These are all the same movie, it's 1:48.36 long with 5,894 MBs. Keeping one audio and one subtitle.
I usually set Rebuilder to run with 3 encoders to keep the temps down. The beauty of having extra cores is that you can burn, surf, listen to music or whatever all at the same time with no worries.
With my old computer which was a single core also with 2 gigs of memory (but that memory was very old, I can't even remember it's speed). This movie would have probably would have taken 3 to 4 hours. I remember doing some full backups that would take 5 to 6 hours.
With one encoder = PREPARE/ENCODE/REBUILD completed in 74 min.
With two = PREPARE/ENCODE/REBUILD completed in 43 min.
With three = PREPARE/ENCODE/REBUILD completed in 34 min.
With four = 28min

[UncasMS]

thanx a lot, ipaulo

those are impressive numbers!

[Chewy]

2 vs 1 is 72% faster
3 vs 2 is 26.4% faster
4 vs 3 is 23.2% faster

multitasker heaven indeed

I wonder with 64 bit and 4 gigs of ram if there would be any benefit, unless you were photoshopping
and dvdrebuilding at the same time

[cynthia]

Realized that these times where a lot faster than my current PC - so I went out and got one Intel Q6600. Will be interesting to see the encoding times with this one.

[soup]

If locoeng sees this, you can bet on what is going to be on his shopping list.

[UncasMS]

after your encoding tests, cynthia, the DVF Grim Rippers we will be proud to nominate you our latest honorary member

[soup]

I second that.

[ipaulo]

Here you go katz this is a demo that will explain the benefits of multi-core processors.

http://www.intel.com/products/processor/core2quad/demo/demo.html

@cynthia as suggested by Chewy be sure to use Artic Silver 5 or something compatible. This is the one I got, Max temp is 65c. I may OC in the future if I ever get AC in this room.

http://processorfinder.intel.com/details.aspx?sSpec=SL9UL

@Chewy I had thought about 64bit and 4 gigs, but found out that windows will only see something like 3.2 gigs and some older apps may not run correctly. I believe you had a thread on this subject, but I can't seem to find it. I had heard this from a few other people as well. So I just decided to go with 32 bit and 2 gigs.

[Chewy]

the bit thing(32 vs 64) defines/determines how much memory can be addressed/mapped by windows

32 bit can only address 4 gigs, since windows maps memory for video, etc then you are left with less than 4 gigs of physical ram that it can see, same reason your swap files is limited to 4 gigs max. Now win xp 64 bit and vista 64 bit extend that limit to the unbelievable amount of 16 million gigabytes, however motherboards and other hardware hold it down to 8 to 256 gigs.

With quad core use growing I wonder, like Uncasms refered to earlier, is even 3.2 gigs enough for 4 cores? I guess gaming and photoshop would be big users?

Many quad core enthusiasts are going to water cooling