Originally posted by: Foamfoot
i just put together my second system - such a great feeling for us newbs when that puppy posts - and was hoping to get some basic overclocking help. i read the the other post about the 845p and it seems like people are getting some great numbers with this board. i was hoping someone could take a sec and give me some idea of some basic bios changes to get the most out of this system.
here's what im running, P4 1.8a 400mhz, 512 DDR Corsair 3000 C2 Platinum XMS series, Radeon 9700, Alpha Pal CPU Heatsink and a modded well ventilated case; running win xp. temps right now are 30/34 Celcius.
these are the options in the BIOS with current defaults:
Default CPU - 1.5000
CPU Voltage - 1.500
Spread Spectrum - Enabled
CPU Host Freq. - 100
Fixed AGP/PCI Output Freq -
CPU:AGP Clock Ratio - Auto
AGP/PCI Freq. - 66/33
DDR:CPU Ratio - Auto
DDR Speed - 266M
AGP Voltage - 1.5
DDR Voltage - 2.5
RAM settings are top to bottom: 2-6-3-3.
thanks in advance and thanks for all of your great posts on part selection and building.
it's really tough to tell you one way or another because each system is different. What I can do is guide you through the steps. First increase the CPU voltage to 1.75 or so as a safe limit. Up the DDR voltage to 2.6 or 2.7 to give some overclock room. Then lock the AGP/PCI to 66/33
Then set the DDR:CPU ratio to 2.00 to eliminate your memory from the equation. Up your FSB (Host frequency) to 133 and try it out. See if you can run everything normally. After that try 140 and see what happens. Keep moving up a little at a time until you find the limit. You'll find the limit by not booting into windows, restarting, crashing etc. Then back down 2Mhz at a time until you find the limit of the CPU. They change the DDR:CPU ratio to 2.5 and see if everything works fine. and then try 2.6 and see what happens. If the system becomes unstable back down the FSB and try a high memory setting. Keep doing this and going back and forth between FSB and Memory until you find a setting you feel is good for both high performance on the CPU side and the memory side.
Let me give an example.
right now you're CPU is running 1800Mhz on 100Mhz FSb so it's 100x18 (18 is the CPU multiplyer)
if you move to 133 you're doing 133x18=2394Mhz that's an overclock of 594Mhz on the CPU side by just an overclock of 33Mhz on the FSB.
If you push it to 140 you'll end up at 2520Mhz which is a great overclock. You could then try your memory at 2.5x which would make your memory run at 350Mhz
the memory runs like this 140x2.5=350 FSb times memory multiplyer equals the memory speed.
That is a great overclock for your system if you can get it stable...you could even try 2.66 memory multiplyer and get 372Mhz memory (140x2.66=372.4)
if that's no go try lowering to 138 and adjust the memory settings until you are stable. so you may be able to run 138FSB with 2484Mhz CPU and 367Mhz memory.
It's really a matter of trial and error...if it doesn't work back down a notch and try it again.
don't forget that you can always add a bit more voltage to the vcore(CPU) or vDIMM(memory) to get a stable setting. the Albatron undervolts just a bit so the limit for your CPu voltage should be around 1.825 which is about 1.75 actual voltage (about the limit of the P4) and the memory can go to 2.7 without harm.
for a refrench my P4 2.26 is wunning on a 17x multiplyer (native 133Mhz FSB). So I run a 158Mhz FSB locking the AGp/PCI to 33/66 and running memory at 2.66 which translates to 2.68Ghz CPU and 421Mhz Memory with my CPU voltage set to 1.825 in bios and my memory voltage set to 2.6 in bios. The actual voltage to my CPU is 1.74 which is within the limit.
PS: YOU ALWAYS want to lock the PCi/AGp to 33/66 to avoid overclocking the AGP cards and the PCI cards with the mobo/CPU.
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