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Topic Title: New to O/C'ing - what do these BIOS values do?
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Created On: 07/01/2005 11:13 AM
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 07/01/2005 11:13 AM
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I've got a Sempron 2800+ (Abit NF7S v2.0 mainboard, 512Mb DDR400 Corsair value Select RAM). When I start up, the BIOS reports the memory frequency as DDR333. I figure that's because the FSB is running at the default of 166MHz. But if I increase the FSB to 200, the system won't boot. So far, I've managed to get to 190 (50% stable) or 180 at complete stability - which translates to about 2.17Ghz for the CPU. Not bad for a start. I ran Prime95 for an hour and just using the boxed AMD cooler maxxed out at 52 degrees C.

But now the questions is - how can I tweak a little further? Specifically there are some setting in the BIOS (SoftMenu III):

DDR Vcc adjustment range - should I be changing this as I adjust the FSB?

Multiplier Factor - this seems to have no effect, as I presume the Sempron is locked?

CPU Core Voltage - again, how does this affect the O/C?

CPU FSB/DRAM ratio - want to make sure I'm running synchronously, so I'm keeping this at Auto. Is that right?

Memory Timings (Optimal/Aggressive/Turbo etc) - what do these do? I think the RAM is CAS3, so probably no joy fiddling with these...?

There's one last mysterious setting - CPU Interface. This states Enable for overclocked settings and Disable for normal settings. Not sure what effect this has. Any ideas?

Oh, by the way - I have a crappy Eagle 350W PSU:
Voltage: +3.3V @ 28A, +5V @ 35A, +12V @ 16A
Current: -5V @ 0.3A, -12V @ 0.8A, -5VSB @ 2A

Hope someone can help me sort all this out!

 07/01/2005 03:54 PM
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Hi gihe,
I am pretty new to this stuff myself, but I will try to answer your questions.
1. DDR Vcc (VDIMM) - this can be increased as the FSB is increased, should the RAM become unstable. Given that you have DDR400 ram, which can be run at 200MHz, it should not be necessary to do so, provided that you don't go much beyond 200MHz.

2. Yes, the multiplier is locked.

3. CPU Core voltage (VCORE) - This can be increased to restore stability as the FSB is increased.

4. As I understand it, yes, auto should be fine for you to run your DDR400 ram with FSB 200MHZ.

5. Memory timings - Unfortunately I have not had luck changing this from Optimal to anything else. I too have Corsair Value select RAM 512MB, but it is supposed to run at CAS 2.5.

6. Yeah, I would like to have that answered too...

As additional info - I have a 3000+ Socket A on an MSI K7N2 Delta2 LSR mobo that runs at 200FSB. CPU interface - Optimal; Ram - Auto @ default VDIMM; VCORE 1.8V.

For more info check out this link Overclocking Guide' ">
 07/01/2005 04:57 PM
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Thanks for that. The guide is pretty helpful.
Still can't get anywhere near 200MHz though... /sad.gif' border='0' style='vertical-align:middle' alt='sad.gif' />
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