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Are Multicores Worth It?

by darkchild
Tags: cache, multicore, multiprocessor
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darkchild
#1
Nov19-10, 11:46 PM
P: 150
I am shopping for a new computer and I want the largest cache size possible. I've found a Dell with an AMD Phenom II X6/9MB of cache. I only understand the basics of multicore technology, and the research I've been doing online suggests that current software and operating systems are not yet able to take much advantage of it, especially anything beyond a dual core processor. I'm wondering if 6 cores could actually slow things down. Would something like a quad core with 8MB of cache be a better choice?


Thanks.
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rcgldr
#2
Nov20-10, 01:46 AM
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P: 7,133
I assume that Windows will split up any multi-threaded application to use one thread per core if they are available. Some applications, such as video renderning applications, will use all the cpu cores and also hyperthreading if it's available. In addition, some video rendering applications can use the video card gpu to speed up rendering.
darkchild
#3
Nov20-10, 03:05 AM
P: 150
Quote Quote by rcgldr View Post
I assume that Windows will split up any multi-threaded application to use one thread per core if they are available. Some applications, such as video renderning applications, will use all the cpu cores and also hyperthreading if it's available. In addition, some video rendering applications can use the video card gpu to speed up rendering.
Yep. The problem is, I doubt that much of the software I use can make use of multithreading. I do like to use multiple programs at once, but nothing more intensive than, say, MATLAB, an email application, a web brower, and a music player.

Negatron
#4
Nov24-10, 03:20 PM
P: 58
Are Multicores Worth It?

It certainly would not slow things down (unless the cores themselves are slower), but it won't speed things up either. For value's sake it's best to keep it at most 4 cores, but 2 would be ideal.
Pattonias
#5
Nov24-10, 07:30 PM
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P: 378
I use six cores, and I am very satisfied. Being able to run a torrent, scan for viruses, and listen to music while playing a game all at the same time without impact on performance is awesome. Many games will take advantage of two cores, so I would say that having more than two is good because windows will put all the background processes onto the cores the game is not actually using. Many of the premium newer games take advantage of up to four cores, so having six is nice for the same reason. The back-up processes are handled on the cores not being used by the game.

The speed of the game is actually dependent on the speed of the processors themselves. So don't be mislead by the multiple cores in that respect.

I will say that for normal computer use, anything more than a dual core is overkill. For gaming I would recommend starting with a quad.
hamster143
#6
Nov24-10, 08:03 PM
P: 986
Most CPU-heavy applications can be (and usually are) adapted to make good use of four physical cores with low overhead.

Logical processors (hyperthreading) are generally less useful, and can be completely useless for many applications, so, for example, if choosing between Intel Core i7 950 (four cores + hyperthreading, 3.06 GHz, $280) and Intel Core i5 760 (four cores, 2.8 GHz, $175), I'd recommend to go with the i5 unless you have too much money.

I'd also recommend not to buy anything now, Intel is less than two months away from releasing a new line of processors, you'll have a better choice and possibly lower prices. Much of the high-end Intel product line is seriously overdue for some repricing. Newegg does not even carry any i7 9xx's lower than 950 any more, because the MSRP on 920-940 does not make any sense.

Personally, I'm waiting for January and then I'm going to go nuts on newegg. The plan is to get a i7-2600K, 16 GB of PC1600 memory, and some liquid cooling on top of that. My home CPU is going to be five years old next month, time to upgrade.
rcgldr
#7
Nov24-10, 08:16 PM
HW Helper
P: 7,133
On a side note, one of the advantages of the i7-9xx sereies is they have more pins and support more pci-express lanes. This doesn't help much unless you plan to use multiple pci-express cards like a pair of video cards for gaming. Some sound cards are also pci-express, but they don't use a lot of pci-express lanes.
hamster143
#8
Nov24-10, 08:22 PM
P: 986
Quote Quote by rcgldr View Post
On a side note, one of the advantages of the i7-9xx sereies is they have more pins and support more pci-express lanes. This doesn't help much unless you plan to use multiple pci-express cards like a pair of video cards for gaming. Some sound cards are also pci-express, but they don't use a lot of pci-express lanes.
I'm not sure if that's really the case. I think that the additional pins of the 9xx are there because the 9xx has a triple-channel integrated memory controller and 8xx's and below are only dual-channel.
rcgldr
#9
Nov25-10, 02:43 AM
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P: 7,133
Quote Quote by hamster143 View Post
I'm not sure if that's really the case. I think that the additional pins of the 9xx are there because the 9xx has a triple-channel integrated memory controller and 8xx's and below are only dual-channel.
Depending on the motherboard (for example X58), i7 900 series handle 32 or 36 pci express lanes, while the other intel cpus and motherboard chipsets are 16 lanes.
hamster143
#10
Nov25-10, 05:00 AM
P: 986
I'm pretty sure that I've seen LGA 1156 motherboards that can handle more than one PCI-Express x16 card.
rcgldr
#11
Nov25-10, 07:37 AM
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P: 7,133
Quote Quote by hamster143 View Post
I'm pretty sure that I've seen LGA 1156 motherboards that can handle more than one PCI-Express x16 card.
In that case, each one gets 8 lanes (or less).
dreiter
#12
Dec5-10, 07:00 PM
P: 57
To answer the OP, essentially ALL new software and operating systems will take advantage of multiple cores. Recent games utilize 2 or 3 (sometimes more for strategy games), and major software packages like Photoshop, Solidworks, Mathematica, etc. are all now taking advantages of multiple cores.

But the biggest thing to keep in mind here is not how programs are able to utilize the cores now, but how well they will in one, two, or three years. Programs will only get better at using more cores, so the solution that makes the most sense is a high core CPU. That is, if you can afford it. :D


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