CPU speed vs RAM speed

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General Mailbox

Greetings.
I have a 3 general questions. If I understand my readings so far, the FSB
(Front Side Bus) is the speed at which the CPU delivers / accepts data
outside of itself. The processing speed of the CPU is rated by the FSB
multiplied by a number set by the manufacturer, which seems to be adjustable
from what I gathered.
Question 1 (two part): Since RAM chips are rated with a set speed, how can
one expect all data processed through them to be as fast as the CPU? Won't
the RAM slow things down becoming a bottleneck? My benchmark readings is
showing that I have a CPU of 6 x 133Mhz (~800Mhz), and my RAM is PC100 not
the PC133.
Question 2: I have 3 slots for memory with 2 used for 128MB and 1 for 256MB.
Does it make a difference in which order they are placed in the slots (banks
0,1,2)?
Question 3: If one RAM is rated at 133Mhz and the other two rated at 100Mhz,
will that be a problem?

Thank you for your time in helping me understand what I'm doing.
Best regards,
Kevin
 
General Mailbox said:
Greetings.
I have a 3 general questions. If I understand my readings so far, the FSB
(Front Side Bus) is the speed at which the CPU delivers / accepts data
outside of itself. The processing speed of the CPU is rated by the FSB
multiplied by a number set by the manufacturer, which seems to be adjustable
from what I gathered.
Question 1 (two part): Since RAM chips are rated with a set speed, how can
one expect all data processed through them to be as fast as the CPU? Won't
the RAM slow things down becoming a bottleneck? My benchmark readings is
showing that I have a CPU of 6 x 133Mhz (~800Mhz), and my RAM is PC100 not
the PC133.
Click to expand...

Computers are full of bottlenecks of this type, where one component is
faster than the other. This is why caches are used so extensively
and why they can have such a substantial impact on overall
performance. In this specific instance the CPU cache retains
recently\frequently used items from RAM so as to speed up the
processing.

Question 2: I have 3 slots for memory with 2 used for 128MB and 1 for 256MB.
Does it make a difference in which order they are placed in the slots (banks
0,1,2)?
Click to expand...

It probably doesn't but consult the user's manual for your specific
motherboard make and model. Some older boards did have a module size
sensitivty and for these the rule was to put the largest module in the
first (bank 0) slot, second largest in bank 1 and third largest in
bank 2. But I haven't seen this characteristic on more recent
motherboard models.
Question 3: If one RAM is rated at 133Mhz and the other two rated at 100Mhz,
will that be a problem?
Click to expand...

A bit of a problem. All of your RAM will operate at 100 mhz.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2008)
On-Line Help Computer Service
http://onlinehelp.bc.ca
Syberfix Remote Computer Repair

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."
 
Thank you so much, Ron.
I was thinking that everything from the processor went through RAM before
being distributed to the varying processes. However, now that the CPU
cache(s) are talked about in the fashion you speak of, this leaves me
wondering "What type of information is stored in RAM then?" I had thought
it was the call table(?) for each program running so the computer would know
where to go next on the drive for the related program modules & drivers,
then loading them into RAM as RAM is faster than accessing the hard disk
drive. So if RAM is set at 133Mhz, what good does a 800Mhz CPU clock do?
Just that it can handle 6 different things at 133Mhz speed?
I'm obviously fairly new to the hardware end of things. *smiles*
Thanks again!
Kevin

|
| >Greetings.
| >I have a 3 general questions. If I understand my readings so far, the
FSB
| >(Front Side Bus) is the speed at which the CPU delivers / accepts data
| >outside of itself. The processing speed of the CPU is rated by the FSB
| >multiplied by a number set by the manufacturer, which seems to be
adjustable
| >from what I gathered.
| >Question 1 (two part): Since RAM chips are rated with a set speed, how
can
| >one expect all data processed through them to be as fast as the CPU?
Won't
| >the RAM slow things down becoming a bottleneck? My benchmark readings is
| >showing that I have a CPU of 6 x 133Mhz (~800Mhz), and my RAM is PC100
not
| >the PC133.
|
| Computers are full of bottlenecks of this type, where one component is
| faster than the other. This is why caches are used so extensively
| and why they can have such a substantial impact on overall
| performance. In this specific instance the CPU cache retains
| recently\frequently used items from RAM so as to speed up the
| processing.
|
|
| >Question 2: I have 3 slots for memory with 2 used for 128MB and 1 for
256MB.
| >Does it make a difference in which order they are placed in the slots
(banks
| >0,1,2)?
|
| It probably doesn't but consult the user's manual for your specific
| motherboard make and model. Some older boards did have a module size
| sensitivty and for these the rule was to put the largest module in the
| first (bank 0) slot, second largest in bank 1 and third largest in
| bank 2. But I haven't seen this characteristic on more recent
| motherboard models.
|
| >Question 3: If one RAM is rated at 133Mhz and the other two rated at
100Mhz,
| >will that be a problem?
| >
|
| A bit of a problem. All of your RAM will operate at 100 mhz.
|
| Good luck
|
| Ron Martell Duncan B.C. Canada
| --
| Microsoft MVP (1997 - 2008)
| On-Line Help Computer Service
| http://onlinehelp.bc.ca
| Syberfix Remote Computer Repair
|
| "Anyone who thinks that they are too small to make a difference
| has never been in bed with a mosquito."
 
General Mailbox said:
Greetings.
I have a 3 general questions. If I understand my readings so far, the FSB
(Front Side Bus) is the speed at which the CPU delivers / accepts data
outside of itself. The processing speed of the CPU is rated by the FSB
multiplied by a number set by the manufacturer, which seems to be
adjustable
from what I gathered.
Click to expand...

Not always adjustable. And if so, there's limits and negative connotations
down the line.
Question 1 (two part): Since RAM chips are rated with a set speed, how can
one expect all data processed through them to be as fast as the CPU?
Click to expand...

If this was a serial line regarding RAM to cpu, I'd agree with you.

Won't
the RAM slow things down becoming a bottleneck?
Click to expand...

No. Your basis of assumption is incorrect.

My benchmark readings is
showing that I have a CPU of 6 x 133Mhz (~800Mhz), and my RAM is PC100 not
the PC133.
Question 2: I have 3 slots for memory with 2 used for 128MB and 1 for
256MB.
Does it make a difference in which order they are placed in the slots
(banks
0,1,2)?
Click to expand...

It can for full utilization in some cases.
Question 3: If one RAM is rated at 133Mhz and the other two rated at
100Mhz,
will that be a problem?
Click to expand...

Not a problem. Defaults to slowest RAM MHz.
Thank you for your time in helping me understand what I'm doing.
Best regards,
Kevin
Click to expand...

Don't have clue what you're doing.
Dave
 
General Mailbox said:
Thank you so much, Ron.
I was thinking that everything from the processor went through RAM before
being distributed to the varying processes. However, now that the CPU
cache(s) are talked about in the fashion you speak of, this leaves me
wondering "What type of information is stored in RAM then?" I had thought
it was the call table(?) for each program running so the computer would know
where to go next on the drive for the related program modules & drivers,
then loading them into RAM as RAM is faster than accessing the hard disk
drive. So if RAM is set at 133Mhz, what good does a 800Mhz CPU clock do?
Just that it can handle 6 different things at 133Mhz speed?
I'm obviously fairly new to the hardware end of things. *smiles*
Thanks again!
Click to expand...

All processing occurs within the CPU and the instructions and data
being worked on are stored within the CPU in registers. Only when
the CPU requires something that is not in the registers does any
outside access occur. First it checks the L1 cache (highest speed)
for the required items. If they are not there then it looks to the L2
cache. Next to be checked is the RAM. And if the required item is
not in RAM then it has to be loaded from storage (e.g. the hard drive
or CD/DVD) or obtained from user input (keyboard/mouse etc.)

So there is no 1 to 1 relationship between CPU processing and RAM. The
CPU can process many instructions in between accesses to RAM and most
often does so. So the speed of the CPU and the speed of the RAM are
not interdependent.

Hope this clarifies the situation.

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2008)
On-Line Help Computer Service
http://onlinehelp.bc.ca
Syberfix Remote Computer Repair

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."
 
There is no serial line from the RAM to its bus system. It has parallel
lines. Think of it as a supply with lots of pipes feeding one big pipe
which eventually feeds the cpu. The cpu has control of RAM on what is fed
to it, and what it writes to RAM.
RAM contains scratch pad data used by the cpu, and open files. In some
cases, the video bios and system bios is cached in it as well.
Dave
 
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