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Pentium 4 and Cache
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embermage13
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Dec 9, 2000, 01:06 PM
 
I was at Intel's site loking at P4 info, and it said it only had 256k cache. Well, doesn't the G3 have 512k (except the iBook which I think has 256), and the G4 1MB? If so, then am I missing something? Are the two cache's different types?

Thanks,
Kyle
     
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Dec 9, 2000, 01:28 PM
 
yea the 256k is level 1 cache which is on the proccessor, the g4 has 1mb L2 backside cache which is not on the processor, the diffence between L1 and L2 is that the processor can communicate faster whith the cache memory when its on the chip itself, the draw back though is that you cant put as much on the chip as you can when its not on the chip like the g4
     
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Dec 9, 2000, 10:03 PM
 
1 meg of backside L2 is better than 256K of on-die - the new G3's have 256K on-die...

Cipher13
     
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Dec 10, 2000, 05:00 PM
 
This all depends on which G3 we are talking about. Some G3's have 1MB L1 cache...otherwise everything seems to be correct.
     
acedloring
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Dec 13, 2000, 02:44 PM
 
The Powerbooks, even the new Firewires, use a 1mg L2 cache running at 5:2. The G3 towers, G4s and Cube also use either a 512 or 1mg L2 cache. The only processor that doesn't use this are the newest ibooks which use an entirely new G3 chip called the 750cx instead of the 750 which is used in all the other models. The 750cx, from what I understand, uses an on-die 256k L2 cache instead. Because this cache runs at full processor speed, it is said to be faster than a 512k L2 cache running at half the processor speed. However, the on-die 256k L2 cache is still significantly slower than the 1mg L2 cache presently in the Firewire Powerbooks. I think the new ibooks use this on-die cache because it consumes less power and really helps in increasing battery time. Anyway, hope this helps...
     
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Dec 17, 2000, 11:29 PM
 

Actually, the Pentium IV has a 256 L2 "transfer" cache. Whatever the hell that is. I'm assuming it's on chip. It's similar to the G3 750cx.

The G5 will sport 128K L1 on chip Cache, 512k L2 on chip cache, and 1MB L3 backside cache. Not only that, but IBM has a new chip they've just announced finishing the core. It leaves plenty of room for growth up to 10GHz. I has the cache mentioned above and is processed at .13u microns. (Petnium 4 is at .18u.)
www.chips.ibm.com
"…I contend that we are both atheists. I just believe in one fewer god than
you do. When you understand why you dismiss all the other possible gods,
you will understand why I dismiss yours." - Stephen F. Roberts
     
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Dec 18, 2000, 12:48 AM
 
yea and when will we be seeing these chips...hmmm 10 years from now if were lucky
     
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Dec 18, 2000, 07:11 AM
 
Originally posted by t_hah:
This all depends on which G3 we are talking about. Some G3's have 1MB L1 cache...otherwise everything seems to be correct.
There is no G3 with 1 meg L1 cache. There are G3's with 1 meg L2 cache.

Cipher13
     
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Dec 19, 2000, 09:01 AM
 
The on-die runs at same speed 1:1 as cpu so you are looking at 500 mhz L2. And most will also have an L3 cache. Small, slow - in some cases non-existent L2 caches were the worst performing machines ever created.

I'd suggest doing some reading over on ChipGeek and Tom's Hardware along with front side bus, DDR, and get an understanding of what 2001 will likely offer.

Changes in the Pentium4 means that operations that once relied on FPU now use a newer processing unit - forcing rewriting of software that relied on fpu as well as new benchmarking.

Now if AMD and MOTO would get together and get some decent yields at higher clocks...
     
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Dec 19, 2000, 01:09 PM
 
This G3/400/512K has 64K L1 (on die) & 512K L2 (backside). (Sonnet Crescendo PCI card)
     
   
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