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Cache sizes on C2D

A

Anti-Hero

Limp Gawd
Joined
Jul 22, 2006
Messages
324
I currently have a E6400@2.6 GHz (not a very good overclock but I've been lazy) and I know it has 2MB of L2 cache. The E6600 (or 6420, etc.) has 4MB L2 cache. Is that 2MB difference going to be noticable at all in gaming?

edit: Damn I need to edit my sig!
 
For gaming, the difference will be very minimal, in the order of 1-3%. However, if you do any form of distributed computing like Folding@Home, the cache will matter more since some workunits love bigger cache.

 
In all honesty I know very little about gaming, but I've read many times the size if L2 cache is sort of minimal for gaming. I do know for a fact that L2 cache size is very important to the folding clients. (single cpu, WinSMP, the Linux SMP) I have a E6420 and a E6400, both folding 24/7, same mobo, same RAM, the only difference is the overclock. The E6420 is OC'ed to 3.0 GHz and the E6400 is only OC'ed to 2.6 GHZ. With a 400 MHz advantage the E6420 is, on average, about 12 mins faster than the E6400 for the times per frame deal (tpf) I wouldn't think 400 MHz would make that big a difference, but it does.

Edit: Oh yeah, both rigs were folding a p2610 WU. I've since retired the E6400 from folding 24/7. (I may have got a "dog" for a E6400 cpu, I can't get it above 2.6 GHz cool and dependable enough for 24/7 folding)
 
As I understand the larger caches may limit overclocking (E6400's clocking higher than E6420's for example) but I still have the 4MB as I felt like I was getting something for that extra $2 different or whatever it was.... not exactly the most logical reasoning, but works for me, and my chip runs at 3.2Ghz no problems, cool (~55 degrees C after several hours full load) @ 1.35 vcore, which I believe is stock. It can run Orthos longer at 1.40 vcore and only runs a small bit hotter. Good OCers these chips, for the most part, so yeah, a E6400 that won't go above 2.6 Ghz sounds iffy.
 
more cache = more performance. The more instructions the CPU can cache and access locally without going to main memory, the less time it spends waiting. And waiting = slowdown. Even in games.
 
It's not noticable in games, at all reallyl.

In something like encoding (if you burn a lot of shows like me..), it helps.
 
2-3% difference games seems to be the concensus among many sources for 2mb cache cpus versus 4mb cache. this is an imperceptible difference that can easily be covered elsewhere (50mhz increase in clock speed)
 
Not enough to warrant a upgrade. Quad core in the other hand. Come July and you'll get your wish.
 
silent-circuit said:
E6400 that won't go above 2.6 Ghz sounds iffy.
Click to expand...

Yeah, I havent' messed with it too much. Leaving all the voltages on auto it won't go above 2.6 stable. Hell, I decided to up the FSB to 400MHz, set the CPU/DRAM to 1:1 (so it's at DDR2 800) and upped the Vcore to 1.4 and the dram v to 2.2 and it won't even post. I'm on stock cooling but that shouldn't be the limiting factor in it posting, I would think. The room it's in is maintained at 70* F, as well.

Any clues?
 
Anti-Hero said:
Yeah, I havent' messed with it too much. Leaving all the voltages on auto it won't go above 2.6 stable. Hell, I decided to up the FSB to 400MHz, set the CPU/DRAM to 1:1 (so it's at DDR2 800) and upped the Vcore to 1.4 and the dram v to 2.2 and it won't even post. I'm on stock cooling but that shouldn't be the limiting factor in it posting, I would think. The room it's in is maintained at 70* F, as well.

Any clues?
Click to expand...

vcore 1.4 may be too low for a 400 x 8 overclock. I need 1.425 for mine to be stable. Try 1.45v at that speed and tighten up the voltage from there as needed.
 
Oh, the memory at 2.2v should not be any different than memory at 2.0v. You're running at the rated speeds already at 400fsb.
 
Yeah, zero reason to up voltage to the RAM -- DDR2-800 synced is the same as DDR2-800 unsynchronized (standard) as far as it's concerned.

Maybe the E6400's need more vcore to stay stable, or maybe I'm just lucky. Also, check vcore with Speedfan, don't go by the BIOS setting. Chances are you're getting less than whatever it's set at, at least slightly, so you might want to push it up a little more, but obviously not too much.
 
silent-circuit said:
Yeah, zero reason to up voltage to the RAM -- DDR2-800 synced is the same as DDR2-800 unsynchronized (standard) as far as it's concerned.

Maybe the E6400's need more vcore to stay stable, or maybe I'm just lucky. Also, check vcore with Speedfan, don't go by the BIOS setting. Chances are you're getting less than whatever it's set at, at least slightly, so you might want to push it up a little more, but obviously not too much.
Click to expand...

You are lucky. My vcore in my sig is necessary for 3.2ghz. I wish I could leave it default like yours. My buddy is running the same rig with the stock hsf and runs 1.39vcore to get 3.0ghz.

Then again, you're on h20.
 
I don't believe the 4MB cache size will really begin to show its advantages until the chip actually starts to show its age. By then you'll probably be contemplating an upgrade anyway.
 
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