Vista - CPU L2 Cache Memory setting in Vista

**Brink** · 07-05-2007

How to Set Vista for the CPU L2 Cache Memory Size

...

Click here to read the entire tutorial

**ltwally** · 08-15-2008

Quote: Originally Posted by WildEagle

You obviously know nothing. 4MBs of cache just because it is shared doesn't mean each core sees 4MB's of cache, it means each core has access to 2MB only not the full 4MB's. If each had access to the full 4MB, when multitasking a game and something else that also used that cache there would be problems out the rear.

Take a look at videocards like the 3870X2 which I own, it comes with 1GB of shared videomemory, but each chip only has access to 512MB of video memory at one time.

This is how dual core cpu's and videocards such as the 3870X2 operate, there is no way, that if they operated any other way, they would get anything done.

Wow. Ok, first: check your attitude.

Second: I do know what I'm talking about. That 4meg of L2 cache is dynamically allocated by the two processors. It's one of the crowning achievments that makes the Core2 series so powerful - there is no need for core0 to send L2 data from its cache to core1's "section." Both processors have full access to the entire cache - though only one processor may have access at any given moment. Intel did some really cool and tricky stuff to make this work.

You need to read up on the Core2 series and understand how it works.

On a dual-core Athlon series, their cache is usually labeled as 2x2meg. There is a reason - as each core has a physically seperate cache.

But Athlons do not have the advanced cache that the Core2 series does.

Before you make rude statements, do a little research. The core2 is a special exception to your knowledge, which is otherwise true!!!

**ltwally** · 08-15-2008

I'll do the research for you:

Advanced Smart Cache - Tom's Hardware : IDF Spring 2006: Will Intel's Core Architecture Close the Technology Gap?

Unlike all of your examples: the Core2 series shares its cache. Fully. There is no dividing line, giving core0 2megs and core1 2megs. The cache is dynamically allocated, and each processor has FULL access to the ENTIRE cache.

**Brink** · 08-15-2008

Itwally and WildEagle, lets keep this conversation going without any rudeness. I would hate to have to give out infractions for something so silly if it goes beyond this.

WildEagle,

I'm sorry, but you are mistaken. The Core 2 Duo processors shares the L2 cache fully between the cores. This is a good thing though for you. Your CPU will perform better with this way instead of the L2 cache split up between the cores.

http://download.intel.com/products/p...prod_brief.pdf

Shawn

baconcow · 09-05-2008

Quote: Originally Posted by ltwally

Quote: Originally Posted by Brink

Hi NicoVO, and welcome to Vista Forums.

The Core 2 Quad Q9450 has two Dual Cores in it. Each Dual core has 6144 (6MB) for a total of 12 MB. You would use the Decimal setting 12288 since the L2 cache is shared fully between the cores with this CPU model.

This diagram provided by Itwally can help show this:

Hope this helps,
Shawn

Actually: The Q9450 is a Yorkfield. The Yorkfield is the latest generation of Core2Quad cpu's, and has a single, unified L2 cache.

For these new processors, the following is a correct diagram:

Code:

                FSB
                 |
                 |
--------------PROCESSOR--------------  
|                |                  |
|                |                  |
|            12 meg L2              |
|                |                  |
|                |                  |
|   ------------------------------- |
|   |         |         |         | |
|  core0     core1     core2  core3 |
|                                   |
-------------------------------------

This has a couple major benefits:
1) The Yorkfields have larger cache's, across the board.
2) All four cores can have access to the same data. There is no need to copy it from CacheA to CacheB. Because threads routinely flop around from core to core, this can be a real benefit. Also, it is a benefit for multithreaded apps.

I found out some information while looking through one of Intel's online datasheets. The Q9450 and Q9550 Quad Cores (and other Quad Cores) use 2x6144 KB L2 Caches. This can be found in Intel's datasheet at http://download.intel.com/design/processor/datashts/318726.pdf on page 11. This article refers to the 45nm Intel® Core™2Quad Processor's (Q9000 and Q8000) Series and the Intel® Core™2 Extreme Processor (QX9000 Series).

Quote: Originally Posted by Intel, Document Number: 318726-005, August 2008

The processor is based on 45 nm process technology. The processor features the Intel®
Advanced Smart Cache, a shared multi-core optimized cache that significantly reduces
latency to frequently used data. The processors feature 1600 MHz and 1333 MHz front
side bus (FSB) frequencies and two independent but shared 6 MB of L2 cache (2x6M)
or two independent but shared 3 MB of L2 cache (2x3M) or two independent but shared
2 MB of L2 caches (2x2M).

I would put the 1800 HEX value if I were you. CPU-Z seemed to hit the mark correctly. For those wondering, my CPU multiplier is clocked down from 8.5 to 6.0 due to notebook speed-stepping.

**Brink** · 09-05-2008

Hi Baconcow, and welcome to Vista Forums.

Normally, that would be true with the CPU has independent L2 caches for each core, but this CPU model shares the L2 cache fully between the cores. Because of this you would use the 3000 (Hex) or 12288 (Decimal) settings instead for the full 12 MB.

Hope this helps,
Shawn

baconcow · 09-05-2008

Okay. Sounds good enough. However, I was able to clear up that it is indeed 2x6144 KB portions instead of one 12288 KB portion. So, I assume than that the drawing of the architecture where each core takes from the 12 MB cache is correct?

**Everlong18** · 09-05-2008

Wow, reading this just makes me want to get rid of my Athlon x2 and get my Core 2 now. End of October and I'll have it

**Brink** · 09-05-2008

Quote: Originally Posted by baconcow

Okay. Sounds good enough. However, I was able to clear up that it is indeed 2x6144 KB portions instead of one 12288 KB portion. So, I assume than that the drawing of the architecture where each core takes from the 12 MB cache is correct?

Yep, you are correct for this CPU model. Both cores share the 2x6144 KB L2 caches fully.

**ltwally** · 09-05-2008

The next generation of Intel CPU's is slated for yet another shift. As I recall (off the top of my head), they will have 32 or 64 KB of L1 and 256 KB of L2 for each processor (read: core), and then a large shared L3 cache - much the same as some of AMD's current offering.

**Brink** · 09-05-2008

LOL, now that will be interesting.

07-05-2007
Brink Vista x64 Ultimate SP2, Windows 7 Ultimate x64 25,974 posts	CPU L2 Cache Memory setting in Vista How to Set Vista for the CPU L2 Cache Memory Size ... Click here to read the entire tutorial
My System Specs

08-15-2008
ltwally vista64 323 posts	Re: CPU L2 Cache Memory setting in Vista Quote: Originally Posted by WildEagle You obviously know nothing. 4MBs of cache just because it is shared doesn't mean each core sees 4MB's of cache, it means each core has access to 2MB only not the full 4MB's. If each had access to the full 4MB, when multitasking a game and something else that also used that cache there would be problems out the rear. Take a look at videocards like the 3870X2 which I own, it comes with 1GB of shared videomemory, but each chip only has access to 512MB of video memory at one time. This is how dual core cpu's and videocards such as the 3870X2 operate, there is no way, that if they operated any other way, they would get anything done. Wow. Ok, first: check your attitude. Second: I do know what I'm talking about. That 4meg of L2 cache is dynamically allocated by the two processors. It's one of the crowning achievments that makes the Core2 series so powerful - there is no need for core0 to send L2 data from its cache to core1's "section." Both processors have full access to the entire cache - though only one processor may have access at any given moment. Intel did some really cool and tricky stuff to make this work. You need to read up on the Core2 series and understand how it works. On a dual-core Athlon series, their cache is usually labeled as 2x2meg. There is a reason - as each core has a physically seperate cache. But Athlons do not have the advanced cache that the Core2 series does. Before you make rude statements, do a little research. The core2 is a special exception to your knowledge, which is otherwise true!!!
My System Specs

08-15-2008
ltwally vista64 323 posts	Re: CPU L2 Cache Memory setting in Vista I'll do the research for you: Advanced Smart Cache - Tom's Hardware : IDF Spring 2006: Will Intel's Core Architecture Close the Technology Gap? Unlike all of your examples: the Core2 series shares its cache. Fully. There is no dividing line, giving core0 2megs and core1 2megs. The cache is dynamically allocated, and each processor has FULL access to the ENTIRE cache.
My System Specs

08-15-2008
Brink Vista x64 Ultimate SP2, Windows 7 Ultimate x64 25,974 posts	Re: CPU L2 Cache Memory setting in Vista Itwally and WildEagle, lets keep this conversation going without any rudeness. I would hate to have to give out infractions for something so silly if it goes beyond this. WildEagle, I'm sorry, but you are mistaken. The Core 2 Duo processors shares the L2 cache fully between the cores. This is a good thing though for you. Your CPU will perform better with this way instead of the L2 cache split up between the cores. http://download.intel.com/products/p...prod_brief.pdf Shawn
My System Specs

09-05-2008
baconcow Vista Home Premium x64 3 posts	Re: CPU L2 Cache Memory setting in Vista Quote: Originally Posted by ltwally Quote: Originally Posted by Brink Hi NicoVO, and welcome to Vista Forums. The Core 2 Quad Q9450 has two Dual Cores in it. Each Dual core has 6144 (6MB) for a total of 12 MB. You would use the Decimal setting 12288 since the L2 cache is shared fully between the cores with this CPU model. This diagram provided by Itwally can help show this: Hope this helps, Shawn Actually: The Q9450 is a Yorkfield. The Yorkfield is the latest generation of Core2Quad cpu's, and has a single, unified L2 cache. For these new processors, the following is a correct diagram: Code: FSB \| \| --------------PROCESSOR-------------- \| \| \| \| \| \| \| 12 meg L2 \| \| \| \| \| \| \| \| ------------------------------- \| \| \| \| \| \| \| \| core0 core1 core2 core3 \| \| \| ------------------------------------- This has a couple major benefits: 1) The Yorkfields have larger cache's, across the board. 2) All four cores can have access to the same data. There is no need to copy it from CacheA to CacheB. Because threads routinely flop around from core to core, this can be a real benefit. Also, it is a benefit for multithreaded apps. I found out some information while looking through one of Intel's online datasheets. The Q9450 and Q9550 Quad Cores (and other Quad Cores) use 2x6144 KB L2 Caches. This can be found in Intel's datasheet at http://download.intel.com/design/processor/datashts/318726.pdf on page 11. This article refers to the 45nm Intel® Core™2Quad Processor's (Q9000 and Q8000) Series and the Intel® Core™2 Extreme Processor (QX9000 Series). Quote: Originally Posted by Intel, Document Number: 318726-005, August 2008 The processor is based on 45 nm process technology. The processor features the Intel® Advanced Smart Cache, a shared multi-core optimized cache that significantly reduces latency to frequently used data. The processors feature 1600 MHz and 1333 MHz front side bus (FSB) frequencies and two independent but shared 6 MB of L2 cache (2x6M) or two independent but shared 3 MB of L2 cache (2x3M) or two independent but shared 2 MB of L2 caches (2x2M). I would put the 1800 HEX value if I were you. CPU-Z seemed to hit the mark correctly. For those wondering, my CPU multiplier is clocked down from 8.5 to 6.0 due to notebook speed-stepping. Last edited by baconcow; 09-05-2008 at 04:01 AM..
My System Specs

09-05-2008
Everlong18 Windows 7 x64 1,287 posts	Re: CPU L2 Cache Memory setting in Vista Wow, reading this just makes me want to get rid of my Athlon x2 and get my Core 2 now. End of October and I'll have it
My System Specs

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