Screw P4 Extreme - I want the Pentium-M Extreme!

[MadRat]

The ultimate gamer is not Pentium4-based, but rather PentiumM-based!

P4 Extreme : 3.20-GHz at 1.75v, 8k 3.20-GHz L1 cache, 256k 3.20-GHz L2 cache, 2MB 3.20-GHz L3 cache
P-M Extreme : 2.0-GHz at 1.484v, 64k L1 cache, 1MB 2.0 GHz L2 cache, 2MB 2.0-GHz L3 cache

Both limited to support for up to 2.0-GB of DDR400. The biggest substantial difference would be the ability of the P-M to run much cooler!

 

[lookouthere]

Originally posted by: MadRat
The ultimate gamer is not Pentium4-based, but rather PentiumM-based!

P4 Extreme : 3.20-GHz at 1.75v, 8k 3.20-GHz L1 cache, 256k 3.20-GHz L2 cache, 2MB 3.20-GHz L3 cache
P-M Extreme : 2.0-GHz at 1.484v, 64k L1 cache, 1MB 2.0 GHz L2 cache, 2MB 2.0-GHz L3 cache

Both limited to support for up to 2.0-GB of DDR400. The biggest substantial difference would be the ability of the P-M to run much cooler!

actually it is below
P4 Extreme: 3.2Ghz. at 1.55V, 8kL1, 512kL2 and 2Mb L3
P-M Extreme(Dothan, not banias): 2ghz. at 1.35V, 64kL1, 2MBL2, and 2MBL3

 

[MadRat]

Whats the use of a 2MB L2 cache if its duplicated in L3?

 

[cow123]

1mb cache in L2 he said

 

[MadRat]

Yeah, I said 1MB. But lookoutthere said 2MB.

 

[Sunny129]

Originally posted by: MadRat
Whats the use of a 2MB L2 cache if its duplicated in L3?

its not so much that its duplicated as it is the shear size of the caches. who cares if its duplicated? if the CPU uses up the L2 cache, it has 2 more MB in L3 that it can reference before having to go to main memory. if the L2 cache were only 256KB or 512KB, the CPU would have to resort to using the L3 cache more often than if the L2 cache were bigger. L3 is slower than L2 (in the sense that it is farther from the ALU than the L2 cache is), so the more a CPU can refrain from having to go to L3 b/c L2 is full, the "faster" it will perform.

 

[lookouthere]

the Dothan Pentium M has 2MB L2 cache

 

[MadRat]

An inclusive 2MB-sized L3 coupled to a 2MB L2 would be pointless in all but .0001% of the times the L2 cache data gets an error, right?

 

[Giscardo]

Originally posted by: Sunny129

Originally posted by: MadRat
Whats the use of a 2MB L2 cache if its duplicated in L3?

its not so much that its duplicated as it is the shear size of the caches. who cares if its duplicated? if the CPU uses up the L2 cache, it has 2 more MB in L3 that it can reference before having to go to main memory. if the L2 cache were only 256KB or 512KB, the CPU would have to resort to using the L3 cache more often than if the L2 cache were bigger. L3 is slower than L2 (in the sense that it is farther from the ALU than the L2 cache is), so the more a CPU can refrain from having to go to L3 b/c L2 is full, the "faster" it will perform.

I think that the nature of P4's cache results in L2 cache being duplicated in L3. So there isn't actually more cache if the two different cache levels are the same size. Physically, yes there is 2MB of L3 out there, but if the data isn't in the L2, it's not in the L3, rendering it useless, and probably adding a level of slowdown because you have to check the L3 for the data you want, when you may as well have checked in the RAM to begin with as soon as you knew it wasn't in the L2. Either that or I'm completely wrong. Either way is fine.