Solved

FSB speed limit

Posted on 2002-03-18
2
245 Views
Last Modified: 2011-09-20
Currently, the FSB is 333Mhz , why can it go faster. Is it because the current bus it's not true 32 bit and it's  only 16+16 bit bus, hence the limitation to speed up to 1.0Ghz or something else.



0
Comment
Question by:hhheng
2 Comments
 
LVL 12

Accepted Solution

by:
pjknibbs earned 50 total points
ID: 6879201
I think you're asking, "Why can't FSB go above 333MHz?". Actually, the fastest FSB around is currently 166MHz--to get 333MHz they use trickery to transfer data on both the rising and falling edges of the clock pulses.

As for the reason, it's nothing to do with the number of bits, and PCI is true 32-bit anyway. (SDRAM is actually 64-bit in both its single and double data rate forms). The limitation is this: you have 64 separate data lines running between the CPU and main memory. Whenever you send signals down these lines you're turning them into tiny radio transmitters, and adjacent lines can act like aerials and pick up these signals, thus corrupting their own data. This effect gets worse as frequency rises, so basically there comes a point where you can't reliably transmit signals down a parallel arrangement.

This is why RDRAM was invented--since RDRAM is a serial system and uses very few wires, there's less crosstalk and the signals can go faster.

Oh, and if you're wondering how CPUs can go as fast as they do without encountering this problem internally, it's because the problem diminishes with the size of the wires involved--this is at least part of the reason why the trend in CPU design has been to smaller and smaller transistors.
0
 

Author Comment

by:hhheng
ID: 6879426
Wow.. you really know your stuff well.
Thanks and cheers..
Heng
0

Featured Post

Three Reasons Why Backup is Strategic

Backup is strategic to your business because your data is strategic to your business. Without backup, your business will fail. This white paper explains why it is vital for you to design and immediately execute a backup strategy to protect 100 percent of your data.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

this article is a guided solution for most of the common server issues in server hardware tasks we are facing in our routine job works. the topics in the following article covered are, 1) dell hardware raidlevel (Perc) 2) adding HDD 3) how t…
This paper addresses the security of Sennheiser DECT Contact Center and Office (CC&O) headsets. It describes the DECT security chain comprised of “Pairing”, “Per Call Authentication” and “Encryption”, which are all part of the standard DECT protocol.
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question