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Dual Core Proc: Will single thread app use both cache?
I'm curious about something, and with this I'm clueless. I'm currently running Vista, reason I mention is well, it may make a difference since it's so dual core friendly.

Ok, simple, I'm wondering if games like LFS, or anything else that's only going to use one core, are able to use all available cache memory? For instance, my proc has 2x 1MB, but since the game uses one core, will it only use one core's cache, or is Vista, or the game, LFS for example, able to use all available cache, all 2 MB? Out of nowhere just now I became very curious as the thought came to me, really out of nowhere.

Thanks for input, I always pay it forward with my knowledge in other areas
Quote from DHRammstein :I'm curious about something, and with this I'm clueless. I'm currently running Vista, reason I mention is well, it may make a difference since it's so dual core friendly.

Ok, simple, I'm wondering if games like LFS, or anything else that's only going to use one core, are able to use all available cache memory? For instance, my proc has 2x 1MB, but since the game uses one core, will it only use one core's cache, or is Vista, or the game, LFS for example, able to use all available cache, all 2 MB? Out of nowhere just now I became very curious as the thought came to me, really out of nowhere.

Thanks for input, I always pay it forward with my knowledge in other areas

A dual core processor will always be better than a single core, having two cores means your CPU can process more information at once. So, If you were playing LFS with a single core and you put some music on, you might lose some FPS because LFS can't use all the power. But with a dual core, one core will be dedicated to LFS and the other core will go into other programs.
#3 - Jakg
Depends if it's 2x 1 MB or if it's Shared.

The L1 Cache should be shared between both cores.

(Please note this is just a guess!)
Quote from Jakg :The L1 Cache should be shared between both cores.

uh no i dont think there is a single (consumer) architechture that does cache sharing at such low levels

iirc athlon x2s have no shared cache core2duos share at l2 level (quads however dont) phenom does at l3 and the nex intel core will do at l3 as well
#5 - Jakg
Oh - i'm sure CPU-Z said the cache was shared *embarrased face*
As the question popped up, is there a way to emulate dual core into single core? I mean with games like LFS, can we use both cores with emulation or something?
#7 - Jakg
...no.
No, it's all in the way the game is scripted. Say you had a 2.6ghz dual core, LFS (being as its written for single core processors) will simply see it as a 2.6ghz processor, and the entire game will only use power from the first core. However, with a dual core you can dedicate and ENTIRE core to a single executable, and everything else (background tasks, operating systems, misc apps) onto the other core to maximize efficiency.
~Bryan~
Well.... Hmm. Ok, I have CPUZ, use it often, I'll look in there, then try googling some more, I really hope it's shared, with most apps not being multithreaded it would seem like such a waste, at least, for now.
Shared L2 for C2Ds (and Yonahs too), no shared cache for AMD (i'm not totaly sure about L3 on Phenoms), Intel is moving away from shared L2 on Nehalems (256 kB per core, shared L3 - 4 MB for dual and 8 MB for quads. And 24 MB for octal core server CPUs).

Shotglass (i see Phenoms do share L3, thanks) quads do share L2 too, but only between core 0 and 1 and core 2 and 3. And not between core 0 and 2/3 and other combinations like that because Intel Quads (until Nehalem arrives) are 2 Core 2 Duos packed on a single PCB. The two dies comunicate via the FSB. Nehalem will be a true, native quad (or octal).
Quote from Primoz :Shotglass (i see Phenoms do share L3, thanks) quads do share L2 too, but only between core 0 and 1 and core 2 and 3. And not between core 0 and 2/3 and other combinations like that because Intel Quads (until Nehalem arrives) are 2 Core 2 Duos packed on a single PCB. The two dies comunicate via the FSB. Nehalem will be a true, native quad (or octal).

i know i was just trying to keep it simple
tbh i have no idea how significant the effect is anyway but with intels being highly dependant on their cache i suppose its measurable
Well my Celeron 420 1,6 GHz) at 2,4 GHz does SuperPI at 26 and a bit seconds. That's on a standard desktop, kinda clutered system. It's a single core 512 kB L2 chip. Core 2 architecture.
Quote from Primoz :Well my Celeron 420 1,6 GHz) at 2,4 GHz does SuperPI at 26 and a bit seconds. That's on a standard desktop, kinda clutered system. It's a single core 512 kB L2 chip. Core 2 architecture.

That must be wrong. Which SuperPi test are you running there? No way can a celly @2.4 get 26 seconds.
#14 - Jakg
It's not a Celly, it's an E2140 with 512 KB Cache - it's Core 2 based.
Quote from Jakg :It's not a Celly, it's an E2140 with 512 KB Cache - it's Core 2 based.

Oh right okay, I thought it was an old Celly from the 420 part, wasn't sure that was the name of the new architecture versions.
Not celly, celery.
Jakg it's single core too :P Yeah, i said it's Core architecture. The new cellys pwn!
#18 - Jakg
It's a single core?!

Here they are £32, with a E2140 weighing in at £38. You'd be crazy to buy one!
This makes me want to get excited about my PD 945 coming soon. They gotta run mid to high 30's in superpi, eh?
~Bryan~
Jakg bought it a year ago. There's a dual core celly too, the E1200. It was the cheapest CPU at that time and it wa meant to be a part time CPU as the 22.7. price drops were a few days away. And it was either this CPU and vacation or E6300...

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