Processor Scalability and Linux

[JD]

  On 08/09/2010 06:51 AM, Roberto Ragusa wrote:
> JD wrote:
>>    On 08/08/2010 01:15 PM, Roberto Ragusa wrote:
>>> Are you going to really use a lot of CPU power? (such as video processing)
>>> Probably not.
>>>
>>> If you are just planning to have a fast general-use computer, than
>>> do not worry too much about the CPU, as AMD or Intel and 4 or 6 cores
>>> will not make a real difference to you.
>>> Consider buying a SSD disk for your operating system and your "live" data
>>> plus an additional big traditional disk for your "storage" data.
>>> I assure you that a SSD disk will have much more impact on the speed
>>> of the machine.
>>>
>> Some years ago, I benchmarked a 32 bit application on
>> 3 GHz Athlon 64 and 3GHz Pentium (was latest release at that time).
>> Both machines running RHEL 4.
>> The application consistently completed on the AMD in  half the time it
>> took on the Pentium. The cause of the improvement was IMHO the
>> CPU-Memory bus speeds of the AMD chip. The front side bus of teh pentium
>> could not move the data as fast. And That app was very very cpu and
>> memory intensive, with datasets as large as 3GB!!
>> Furthermore, it was not a multithreaded app.
>>
>> Nowadays, the multicore pentiums have sped up the FSB to respectable
>> speeds of 1.6GHz or perhaps even higher. But I have not kept up with
>> this area of the technology, so I could not address the very latest
>> cpus from AMD and Intel.
> What you say in some way confirms my point.
> In an extreme CPU-bounded case (you said "very very"), the speed
> ratio between the CPUs was about 2:1.
>
> On the other hand, in extreme IO-bounded cases, the speed ratio
> between the hard disk and a SSD can be 100:1.
>
> Consider that I/O intensive tasks are more frequent than CPU intensive
> tasks for the average computer user (just consider booting, folder
> browsing, app loading, data loading, data searching, file copying, ...).
> That is why money spent for a SSD is well spent.
>
> What should one choose between (for about the same total price)?
>
> a) a 40mq house plus a 300km/h car
> b) a 4000mq house plus a 150km/h car
>
> I would say: "go for a) only if you are in car racing, otherwise go for b)"
>
> (note that I applied the 2:1 and 100:1 ratio).
>
No question. You're preaching to the choire.
Disk intensive processes will indeed achieve
that speedup ratio.
The app I tested was used for verifying digital designs.
It's data set was huge and, to add insult to injury, it was
very deeply recursive - thousands of recursion stacks.
If I could AMD's latest and fasted 8-core cpu and
SSD disks on a modern mobo, 16GB high speed ram,
I would have to spend much more than I can part with :)