Duron 800 overclocking: is it better to increase the FSB or the multiplier?

[SickBeast]

I've read that people reduced the multiplier to 5.0 then upped the FSB to like 133mhz...I can't seem to get mine to post at that speed tho...any suggestions? Right now it's running at 1065mhz (112fsb x 9.5 multiplier) should I just leave good enough alone?

 

[TexDotCom]

I am not the be all and end all of computer techs, but here is my explanation:

The K7 family of AMD chips, i.e. Duron and Thunderbird, use a DDR bus. Basically, this takes the bus of your motherboard and doubles it. The Duron should be able to do a 200 MHz effective bus, which is 100 MHz on the board. The Tbird should be able to do a 266 MHz effective bus, which is 133 MHz on the board. By trying to run the Duron with the FSB set to 133 MHz, you are trying to actually run the chip using a 266 MHz (2 x 133) bus. That could be why it will not work at that speed.

I have heard of some Durons that will post and even run quite nicely with the mobo set to the 133 MHz setting. Not all will, though, so you may just have to stick with the bus and multiplier combo you have right now. As always, you can try upping the vcore voltage as the Duron should work just fine up to 1.85v. Make sure you have good cooling for that, though.

Good luck, and I hope that this helps (I also hope I am not toofar off in my explanation. If I am, someone please provide correction, but in a nice way. Thanks.

 

[SickBeast]

great thank you for the info

 

[Garet Jax]

SickBeast,

You will get more performance out of your system by pushing the FSB higher. For example 7.5X133 will result in a faster system than 10X100 even though they both push the CPU the same.

The reason is that the the multiplier only affects the CPU while the FSB affects everything in the computer (CPU, RAM, AGP Bus, PCI Bus). As a result, by increasing the FSB you will be pushing all parts of your computer a little harder. This will result in better performance all around.

Hope this helps.

[EDIT] Missed the other question the first time. You machine may not be POSTing for a number of reasons:
1) You may need to provide a little extra voltage to the chip.
2) Your MB Chipset may not be able to handle a 133 FSB.
3) Your RAM may not be able to handle the extra speed. What are your RAM ratings?
4) If you have control over the AGP or PCI divider, it is possible that they are set incorrectly. AGP speed by default is 66Mhz so you should use the 1/2 divider for 133 FSB. PCI speed by default is 33Mhz so you should use the 1/4 divider for 133 FSB.
5) A lot of motherboards allow the RAM and the FSB to run at asynchronous speeds. Typically the RAM can be set at FSB + [something]. If your setting was FSB 100/RAM 133 and you changed the FSB to 133, your RAM may be trying to run at 166.

I would need a little more information to provide more help.