question about AMD's different CPU's

[Guest]

ok i get all that, just one question more about the L2 and L1 cache. concerning being "cache on die" as apposed to no on the CPU, and all that about running at 1:2 or 1:3 ratio as appose to having cache run at full, where can i see this in my own computer? i think mine says something about having 256k of l2 cache? does that mean since i have 256 mb or ram i am running at full speed of processor or do i have this all wrong? i don't get that concept. thanks

 

[JOJO]

um.... i checked out an article on tom's site and this is what i found...

"Duron is the close brother of 'Thunderbird', the new 'Socket-Athlon'. As a matter of fact the architectures of Thunderbird and Duron are pretty much identical. The only two differences are the size of the second level cache and the core voltage. Thunderbird comes with 256 kB on-die and full speed L2 cache, while Duron has only got 64 kB of that stuff."

I don't think it's a typo or anything, but i'm sure the duron has 64k of L2 cache

thanks anyway though

 

[girish]

hi!
cache and main memory are different, main memory can exist without a cache, cache is processors' accessory which it needs to suffice its need for fast supply of bytes, just as you have your glass with you while all the wine is in the bottle. you fill it as and when you need it and you have it in your hands, no need to stretch your hands to the bottle! 🙂 is this analogy is ok....? 🙂))

anyway, the 256k of cache is the ampount of super fast static RAM that is IN your CPU (is it a P-III Coppermine or a Athlon?) which is running with your CPU, and your RAM might be 128 MB or 256 MB, running at 100 or 133 MHz. btw pls tell me the specs of your system.

the distance between the cache and the processor is important, since the inductances and capacitances over the lines (on the PCB card or the tiny wires connecting to the other die in a hybrid chip)connecting them have their effect distorting the signals, so external caches are always run at a lower speed. on the die, the cache is fabricated on the same substrate as the cpu and the distances between them is very small, so it can be run at cpu speed without any problems.

got it?

girish

 

[girish]

well, i havent seen that article, but relying on what docs i have (Duron data sheets) i am pretty sure Duron has 192k of onchip cache, thats 64k L1 and 128k L2. after all 64k of L2 cache is too small today, 128k is bare minimum - celeron has 128k of it.

girish

 

[JOJO]

this is right from amd's web site

"Q12: Does the AMD Duron processor feature on-chip cache memory? How large are the L1 and L2 caches of the AMD Duron processor?

A12: Yes. The AMD Duron processor features 128kB of on-chip L1 cache memory and 64kB of full-speed, on-chip L2 cache memory. "


check it out at http://www.amd.com/products/cpg/duron/faq.html

 

[girish]

oh! well i just saw that page. and reread the manual (23865.pdf)! and downloaded its revision. and saw its appnote TN13.pdf that has a workaround for the Duron's misreporting of L2 cache size!

i had just started assumed that L1 has to be smaller than L2 (for no logical reasons!) and swapped the figures. it seems i have to read that appote TN13 4 times a day to clear the bug! 🙂 i misreported it too! what a goof-up!!

sorry abt that guys!

girish