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WinRAR vs. Core Parking vs. Core i7 in Windows 7 and Windows 8

AMD FX-8150 v porovnání s Intel 386SX-16 ;-)
Tento článek bude výjimečně v angličtině. Rozhodli jsme se, že dáme zahraničnímu československy nemluvícímu čtenáři příležitost nahlédnout pod pokličku našeho stylu psaní a tvorby recenzí. Jedním z důvodů je někdejší nekorektní zjištění dobrého výkonu AMD Bulldozeru ve WinRARu oproti procesorům Core i7. Rádi bychom tímto i našim zahraničním čtenářům sdělili náš pohled na věc. We decided to write an article in English (actually it's our first) to give a non-Czech/Slovak speaking reader the opportunity to look inside our writing style and review creation. One of the reasons for this is incorrectly measured exceptional performance of AMD Bulldozer over the Intel Core i7 processor. We would like to take the opportunity to show our point of view to our readers abroad.

What happens when you run WinRAR benchmark on Windows 7 in a system with Core i7? Windows 7 uses only 6 threads for a reason not know to us yet. We wrote about that almost two years ago when we tested Core i7 980X aka first 6-core Nehalem.

Intel Core i7 980X - obsah balení
Contents of the box with Intel Core i7-980X from a test kit

On the seventh page we mentioned something like that:

Core Parking is responsible for as little as possible core utilization if the application does not need that (i.e. not to utilize all cores with low load, but to utilize less cores with higher load). The implementation is anyhow odd and with WinRAR it is very well seen, because it's an application that is far from utilizing all cores at full load, while the relatively low load is quite stable.

WinRAR - Core Parking zapnuto

So WinRAR was able to utilize only six of twelve available processor threads due to enabled Core Parking. The same behavior is visible with quad core Core i7, even with the detail that the system gives WinRAR also six threads, but now from only eight available. In other words: one core can be completely unused. The thing is that Core Parking in Windows 7 primarily parks threads, not cores, i.e. although WinRAR uses all cores, there are only two cores loaded including Hyper-Threading. From the Core Parking perspective that behavior is not really correct because the primary reason for Core Parking is to save energy by leaving unused cores in low power state (which is not the case with Windows 7 and Core i7).

When we disabled Core Parking, the operating system provided the WinRAR all available threads. Performance increased by 35% in case of 6-core Core i7 980X using WinRAR 2.91 and by almost 40% in case of 4-core Core i7-2600K using WinRAR 4.10 beta 1 (there is noticeable improvement in WinRAR development over the time).

There is nothing easier than to put all relevant numbers in a chart:

Intel Core i7 2600K (v socketu) AMD FX-8150 v plechové krabici

You can clearly see that WinRAR performs much better on Core i7 with Core Parking disabled. To be honest, we don't know why we forgot about the influence of Core Parking when we made our first Bulldozer review, especially in connection to the fact that we demonstrated it almost two years ago (the way of disabling Core Parking in Windows 7 i either way documented in the internet since the year 2009). We would like to thank to our reader (hladiswho sent us an email about it just after the publication of our first Bulldozer review. We also apologize for missing that „bug“ (really, we shouldn't miss that).

WIFT "WIFT"

Bývalý dlouholetý redaktor internetového magazínu CDR-Server / Deep in IT, který se věnoval psaní článků o IT a souvisejících věcech téměř od založení CD-R serveru. Od roku 2014 už psaní článků fakticky pověsil na hřebík.

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Diskuse ke článku Analyzing Core Parking in Windows 7 and Windows 8 in relation to AMD Bulldozer performance (in English)

Čtvrtek, 24 Listopad 2011 - 11:47 | Anonym | Lepe bych to sam nenapsal. :-)
Středa, 23 Listopad 2011 - 12:59 | Ladislav László | Díky za skvělý odkaz :-)
Středa, 23 Listopad 2011 - 07:25 | Ludek Jelinek | Rád bych, ale ..... viz vyse. Kdyby slo prispevky...
Středa, 23 Listopad 2011 - 07:23 | Ludek Jelinek | Ne, na kompu nemam nainstalovanou cestinu (mozna...
Středa, 23 Listopad 2011 - 00:40 | MACHINA | 15 minut je už asi pryč, nevidím žádné english...
Úterý, 22 Listopad 2011 - 21:52 | Militantní Swičr | Ale já si stejně myslím, že mluví pravdu a ty...
Úterý, 22 Listopad 2011 - 20:53 | vali | Vynikajícím způsobem zpracovaný článek (mám na...
Úterý, 22 Listopad 2011 - 19:21 | MiMo007 | Aha, já to četl jako něco nového. Jakže se...
Úterý, 22 Listopad 2011 - 19:13 | Václav Novotný | Hello DIIT.cz, very interesting article. Not much...
Úterý, 22 Listopad 2011 - 17:12 | roTTen | *vždyť*

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