Intel hyperthreading

[Andersen]

Hi,

I am thinking about buying a new computer.
Is it worth it to pay extra to get an intel with hyper-threading?

Hyper-threading shares the caches, will it not then by also more or less
suitable to get one with 512kb cache?

Some of them say FSB 800MHz, what is that? Is that worth getting?

cheers,
Andersen

 

[Boba & Ilinka]

Hi,

I am thinking about buying a new computer.
Is it worth it to pay extra to get an intel with hyper-threading?

Hyper-threading shares the caches, will it not then by also more or less
suitable to get one with 512kb cache?

Some of them say FSB 800MHz, what is that? Is that worth getting?

Now I would go with
P4-2.8EGHz/800/1M P4-2.8EGhz/800/1M PreScott /1M L2 OD Cache 800MHz
FSB S478 (HT) (Retail) $255.00

There is 1 Mb cache on processor. 800 MHz front side bus means a transfer
"speed" between processor and peripherals.

If you buy a new computer it is worth to add a few % more for better
processor.

Boba Vancouver BC

 

[kony]

Now I would go with
P4-2.8EGHz/800/1M P4-2.8EGhz/800/1M PreScott /1M L2 OD Cache 800MHz
FSB S478 (HT) (Retail) $255.00

There is 1 Mb cache on processor. 800 MHz front side bus means a transfer
"speed" between processor and peripherals.

If you buy a new computer it is worth to add a few % more for better
processor.

Prescott is lower performing than same MHz speed Northwood, the 1MB cache
isn't enough to make up for the longer pipeline. The wise builders will
buy Northwoods while they're still available or wait for the Prescotts at
speeds > 3.4GHz.

 

[Andersen]

Prescott is lower performing than same MHz speed Northwood, the 1MB cache
isn't enough to make up for the longer pipeline. The wise builders will
buy Northwoods while they're still available or wait for the Prescotts at
speeds > 3.4GHz.

Notice I was talking about the 3.04MHz, not the 2.8MHz, maybe at that
speed the 1MB Cache will be ok?

cheers,
Andersen

 

[kony]

Notice I was talking about the 3.04MHz, not the 2.8MHz, maybe at that
speed the 1MB Cache will be ok?

cheers,
Andersen

It's still slower than (same speed) Northwood. Prescott's advantage lies
in where Intel can take it in the future, that it will eventually be
released in models with the clock speeds beyond the (reasonable)
capability of Northwood... that might make it desirable for overclockers
but not for anyone else at the moment.

 

[Andersen]

It's still slower than (same speed) Northwood. Prescott's advantage lies
in where Intel can take it in the future, that it will eventually be
released in models with the clock speeds beyond the (reasonable)
capability of Northwood... that might make it desirable for overclockers
but not for anyone else at the moment.

I understand what you are saying, and am encouraged to buy a northwood
for now after reading on comparisons where prescott hardely gave better
improvement.

Could you, are anyone else, please explain why it is so?

Why is it not reasonable for the Northwood to ever run on clock speeds
that are much higher, while prescott presumable one day will?

Why does a longer pipeline, such as in the prescott, lead to the fact
that a much larger L2 cache is needed, and that 1MB is not enough?
Shouldn't a larger pipeline on the same clock speed lead to faster cpu?

regards,
Andersen

 

[Mike Walsh]

Why does a longer pipeline, such as in the prescott, lead to the fact
that a much larger L2 cache is needed, and that 1MB is not enough?

The length of the pipeline and the size of the L2 cache needed are not directly related. Given the speed difference between CPUs and system memory a larger cache will always improve performance. This is especially important with hyperthreading because the cache must be split between two threads.

Shouldn't a larger pipeline on the same clock speed lead to faster cpu?

No. At any given clock speed a pipeline with more stages will be slower because more operations must be discarded, mostly because of incorrect branching.