Lewis Powell
Posted 6 years, 4 months ago
Joined: 12 years, 5 months ago
I am running a PC with a Pentium 4 630 3GHz, 800MHz FSB, under XP Service Pack 2, on a Gigabyte 81915P Pro motherboard.
It is usually a fast and reliable machine, recently however, it has been running slower, so I did some checking up and found that FSB of the CPU was running at 200 MHz. Am I right in assuming that the Front Side Bus is the same as the External Clock and CPU Host Clock (these are also 200MHz, according to PC Mark05 and my computer’s BIOS respectively)?
If so, how can I restore my original FSB? I would change it (the CPU Host Clock) in the BIOS, but it has a limit of 600MHz. I recently installed Gigabyte EasyTune 5 while in search of a utility to free up some RAM, could this be the problem?
Gordon Drennan
Posted 6 years, 4 months ago
Joined: 12 years, 5 months ago
Re: CPU FSB Trouble
Don't worry, your FSB is actually running at 800 MHz. The problem is that the terminology is confusing. The FSB on your Intel CPU is "quad pumped". That is, it does four data transfer cycles per clock cycle. An FSB that does four data transfer cycles per clock cycle, and is clocked at 200 MHz can transfer data as fast as an FSB that has one data transfer cycle per clock cycle that's running at 800 MHz. So Intel calls it an 800 MHz FSB. But it isn't. Its a quad-pumped 200 MHZ FSB. And that's what the BIOS and other utilities correctly report. That its a 200 MHz FSB.
Earlier CPUs had single-pumped FSB. Then Intel and AMD had the smart idea of double pumping their FSB. That meant they could transfer twice as much data without stepping up the actual FSB frequency. Now Intel is running a quad-pumped FSB. Its the same with RAM. There used to be DRAM. Then there was DDR RAM which transferred data twice as fast by double-pumping the bus. Now there's DDR2 RAM which quad pumps the bus. Intel and AMD and the RAM manufacturers say their products run at 400 MHz or 667 MHz or 800 MHz, but they actually don't. They only actually run at 200 MHz and they're double or quad pumped to be the equivalent in data transfer rate of 400 or 667 or 800 MHz.
