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Thread ID: 38473 2003-10-08 05:46:00 Please Explain MOBO RAM Winston001 (3612) Press F1
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181340 2003-10-08 05:46:00 I am very confused about the specs provided for various machines.
For example, a Compaq NX 9010:

2.0GHz (fine so far - Intel Pentium 4 processor),then we have 400MHz FSB, 512KB L2 integrated cache!
Now..... whats that all about?

I have tried the Webopedia but the explanations are too brief. 		Winston001 (3612)
181341 2003-10-08 06:16:00 > then we have 400MHz FSB,

The "Front Side Bus" does not run at the GHz speed of the CPU, as RAM is not that fast. The FSB sets the speed at which RAM is addressed (400 MHz in this case)

> 512KB L2 integrated cache

The processor has a "buffer" of high speed ram integrated (on-chip) to buffer data, to (try and) improve speed. If the next data needed is in the buffer, its a faster access. If not, its wasted.

If buffers are too large, the time taken to search for the data can be as long as re-acquiring the data, so they are not in the MB range.
RAM located on the Motherboard can't run as fast as the on- (CPU) chip RAM, as there are physical constraints (electrical distance transit times).

The Level 2 refers to where it is in the structure of the chip architecture.

Thats based on my (aging) memory (which has no L1 or L2 cache), so E&OE 		godfather (25)
181342 2003-10-08 06:41:00 Hi Winston

You may find this article helpful, the link was posted by someone recently (?metla) which I bookmarked as it was quite good.

Understanding System Memory and CPU speeds: A layman's guide to the Front Side Bus (FSB) (www.directron.com) 		Jen C (20)
181343 2003-10-08 06:53:00 Thanks Godfather and Jen C. There is obviously more to this than I thought. Good to keep learning. Winston001 (3612)
181344 2003-10-09 07:49:00 >
> > then we have 400MHz FSB,
>
> The "Front Side Bus" does not run at the GHz speed of
> the CPU, as RAM is not that fast. The FSB sets the
> speed at which RAM is addressed (400 MHz in this
> case)

Then what's this on the box my CPU came in that says "400Mhz System Bus"??? <I'm confused >

Mike. 		Mike (15)
181345 2003-10-09 08:08:00 with older systems the fsb is the speed which the cpu access the motherboard chipset and ram. later ones its the speed/bandwidth the cpu access the chipset, ram speed is independant of fsb.

your cpu has a fsb of 400mhz so it really needs a motherboard that suports a 400mhz fsb. ram speed is usally based on fsb. 		tweak'e (174)
181346 2003-10-09 08:18:00 However, my CPU (the same one with the 400Mhz System Bus) is "locked" to 100Mhz (it being a Celeron and all)

that's what confuses me :)

and I have a feeling that my mobo does support 400Mhz... I guess it does, as it supports 533Mhz :)

Anyway, all this new technology confuses me greatly :) I feel I'm now asking more questions here than I'm answering :( Methinks I'm becoming ungeek !!! :O

Mike. 		Mike (15)
181347 2003-10-09 08:26:00 >However, my CPU (the same one with the 400Mhz System Bus) is "locked" to 100Mhz (it being a Celeron and all)

you'll proberly find thats its locked to 4x100mhz = 400mhz. 		tweak'e (174)
181348 2003-10-09 20:28:00 OK I have read further and am gratified at Mike's questions.
I suppose the point is to understand the consequences of this information.
Reading about Front Side Bus and L1, L2, and L3 Cache describes what they are but doesn't really explain what is optimum or best. A bit like learning about 3/4 race camshafts without understanding their influence on motor performance and unsuitability for the average car.
So, presumably different chipsets have their own bus and cache specs.
What should I look for in, say a laptop for the net, music, word processing, and maybe experimenting with copying hours of camcorder tape? 		Winston001 (3612)
181349 2003-10-09 20:57:00 and whats the difference between L1cache and L2 cache.I head there's a L3 cache somewhere!! yingxuan (3330)
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