What is considered synchronous for FSB and RAM

autoMATTic

Distinguished
Nov 23, 2003
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18,510
What is considered synchronous for FSB and RAM when dealing with Intel cpu? I was reading the following article http://www20.tomshardware.com/motherboard/20030812/index.html and he was talking about it. I was wondering because I have a Shuttle AV49N mobo and a Intel P4 2.4B Ghz and Twinmos DDR400 ram. My system was very unstable at 2.4 Ghz, 533Mhz FSB and ram at 400Mhz(200). The only way for it to run stable was for me to underclock my ram to 333(166). Or if I wanted my RAM set to 400(200) the only way to make it stable is to underclock my cpu to 1.8Ghz and 400Mhz FSB.
 

Crashman

Polypheme
Former Staff
Let me congratulate you on getting a garbage board. I doubt that board will run the RAM bus at DDR533, and even if it could, I doubt DDR533 RAM would work at full speed on it. Your DDR400 RAM doesn't even seem to be working at full speed on it.

True sychronicity would be running the RAM at PC2100 speed in Dual Channel mode, but your board doesn't support Dual Channel mode. Your CPU FSB of 533 uses an actual clock rate of 133MHz, the same as DDR266 uses an actual clock rate of 133MHz. But the CPU uses a Quad Data Rate (4x transfers) bus, while the RAM uses a Double Data Rate (2x transfers) bus.

Fact is, there IS no good way to run the P4 2.4B in single channel mode. Since synchronous clocks provide the memory bus with 1/2 the bandwidth of the CPU bus, your best performance comes from running the RAM ASYCHRONOUSLY, trading off better bandwidth for worse memory controller performance.

I can't feel sorry for you, simply because you bought a VIA chipset board.

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autoMATTic

Distinguished
Nov 23, 2003
3
0
18,510
Thanks for replying. Yeah I kind of noticed my board wasn't exactly for "power users" due to its lack of adjustability in the bios. The highest clcok rate you can set the Cpu to in the bios is only 165, for the ram its only like 200, no cpu voltage, etc. But hey it was only like 50 bucks. So basically your sychronous when your Ram clock speed and cpu clock speed are the same? And whats wrong with Via chipsets?
 

Crashman

Polypheme
Former Staff
VIA chipsets are the lowest quality chipsets you can buy, worse than even SiS, and quite frankly explaining why just pisses me off. But if you can search my post for the last couple years you'll find a couple hundred explainations.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
 

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