Need help from you guys/girls

[RShick]

Ok, going to be receiving the following hardware:

Abit IC7 - G
Intel 2.8CGhz - 800 Mhz FSB
Corsair XMS matched 512Mb RAM PC3500 (total of 1Gb)
ATI Radeon 9800 Pro 128Mb Video Card

And some other stuff to round out the system.

Can someone explain some of the overclocking potential of this machine for me? And can you also explain the math behind it. What does my FSB need to be to reach 3.25 Mhz on the processor? What is the biggest bottleneck going to be for me? And anyone with direct experience with the Abit IC7-G, can you help me with the ideal settings in the BIOS? I have no experience with this motherboard, and this is going to be my first attempt at overclocking.

Thanks,
RS

 

[GtPrOjEcTX]

PC2100 = DDR 266 Mhz
PC2700 = DDR 333 Mhz
PC3200 = DDR 400 Mhz
PC3500 = DDR 433 Mhz
PC3700 = DDR 466 Mhz

The type of RAM you get is dependant on what FSB you want to run your system at. If you get a 2.8c stock it is 200FSBx14 multiplier. You cannot change the multiplier, just the FSB.

To get 3.25Ghz, you should run the FSB up to 232. 232*14=3248Mhz.
as for your memory, if you run this in 1:1 ratio, that means you will be overclocking your DDR to PC3700. It may run this, it may not.

If it doesn't then your next step is to change the multiplier to 5:4. This will kill your memory performance, but the only choice if you want to run your PC at 3.25Ghz. 232 / 5 * 4 = 186 *2 = DDR372. So really, you would only need PC3200 to run this, even then, not getting the entire DDR400 out of it.

--------------------------------------

with DDR, the ram runs 2X the speed of the FSB. Ex. In systems with a 133FSB, DDR266 (PC2100) does the job. This is when run 1:1.

However in systems that bump the FSB way up it is impossible for the RAM to run at the 2X the speed.
That's where the ratios of 5:4 and 3:2 come in to play.

If I were to set my FSB to 250, and ran 1:1, that would mean I would need DDR500. However if I set the ratio to 5:4 that means
250 5
--- = -
200 4

The ram would run at 2X the 200 and run at DDR400 (PC3200). This lets the higher setting of FSB without the RAM being the limitation.

Hope that helps you.

 

[RShick]

Thanks for the response, that info helps a great deal.

However, my other concern is the voltages on the different rails. Specific to Intel chips, what do I have to be aware of when overclocking? Should I expect that I am going to have to increase voltage? If so, what do I need to look for?

Thanks,
RS

 

[GtPrOjEcTX]

that's a relatively small overclock. I would expect you could hit that without having to increase your voltages. on the other hand if you you want to run your memory at 1:1 and at PC3700 speeds, you could try bumping your voltages on your ram up. standard I think it is 2.6. Don't go over 2.8.

also if you need to bump your vcore voltage DEFINITELY don't go over 1.7V. I don't like going over 1.65 volts myself. but as I stated, you probably will do fine at default voltage

 

[WaTaGuMp]

Look at it this way if you can get to 250 FSB with a 5:4 mem divider you would be at 3.5 gigs and your DDR would be at 400 running async with your fsb, this is under the rated speed of the 3500 ram so your not going to stress the ram at those settings.

Yes you lose some performance with the 5:4 over the 1:1 but the higher FSB makes things faster and being async helps also, you could always try even higher FSB over what your 3500 is rated to which as he said is 433.