GA-965P-DS3... please explain this

[Scootel2]

I have read this board supports DDR2 1066. I plan on getting a Core 2 Duo 1.8GHz (800MHz FSB) so I can overclock it. The multiplier on this chip is 9 so 9x200FSB = 1.8GHz. So if the memory is 1:1 I really only need DDR2 400? I may be way off but I would like someone to help me understand this alittle better. Im thinking I only need DDR2 800 if I plan to overclock 100% to 3.6GHz (9x400FSB=3.6GHz)

This may sound very dumb but I am new so take it easy on me please...

Anyone who can explain this better to me I would greatly appreciate it.

Thanks

 

[unclewebb]

With a DS3 or any Intel 965 based board you have to run your memory in sync with your front side bus. The lowest you can go is 1:1 so with a FSB of 400 MHz your memory would also run at 400 MHz which is the default frequency that DDR2-800 runs at.

You might not get 9 X 400 out of your E4300 but 8 X 400 is not only possible but quite likely with a minimum of additional CPU core voltage.

Your numbers aren't dumb. They're right on. Happy overclocking.

 

[Scootel2]

unclewebb thank you for the response. A couple more questions...

Lets say I decide to keep everything stock. Wouldn't it be smarter to get DDR2 400 since the timings are better?

Lets also say I only overclock it to the middle of what its capable of. (9x300=2.7GHz) Would this in turn make the FSB 600MHz? If this is correct wouldn't it be better to run DDR2 667MHz for better timings?

Again I am new to this so all help greatly appreciated.

Thanks

 

[Gyrfalcon]

I was under the impresion that DDR is FSB * 2 so 200*2 = 400 while DDR2 is FSB * 4 so it runs 200*4 = 800.

 

[cerebrex]

The DS3 will not make your overclock easy to say the very least. Post your progress and I'll follow it and try to help.

 

[unclewebb]

Here's a CPUz screen shot with a FSB DRAM ratio of 1:1

This has my memory running right at its default of 400 MHz or DDR2-800.

The next screen shot is with a FSB DRAM ratio of 4:5

The FSB ( Bus Speed ) is the same at 400 MHz but 400 MHz * ( 5 / 4 ) = 500 MHz for the memory which is the frequency that DDR2-1000 is designed to run at.

The common FSB DRAM ratios that the Intel 965 chipset offers are:
1:1
4:5
2:3
3:5
1:2

If you wanted to run a nice safe 2700 MHz with an E4300 you could also lower the multi one notch from 9 to 8 and run it at 337 MHz * 8 = 2696 MHz and with a 1:1 memory ratio your memory would be at 337 MHz or DDR2-674 which would be no problem for DDR2-667 memory to run at.

The default for DDR2 memory is 1.8 volts but if you boost that to 2.1 volts, even most cheap memory will be able to run reliably at DDR2-800 speed.

An E4300 with a 9X multiplier combined with a handful of memory ratios will let you run your memory wherever you want it. In my example above you'll notice that in order to run my memory at 500 MHz I had to loosen the memory timings from CL4-4-4-12 to CL5-5-5-15 to maintain stability. Top of the line memory can run CL4-4-4-12 timings at 500 MHz but the performance improvement is minimal and is not really worth the big increase in cost.

 

[magoo]

The math is easy.

FSB is "quad pumped" 200x4=800 FSB, 266x4=1066FSB and so forth.
DDR is "double data rate" 400 hz x 2 = 800hz.

 

[unclewebb]

The DS3 will not make your overclock easy to say the very least.

The DS3 I had last year was one of the most overclocking friendly motherboards I've ever used.

With a DS3 and some generic Micron memory I reliably ran an E6300 at 7 X 472 MHz ~ 3304 MHz .
The only thing I changed was I set the CPU voltage in the bios to 1.35 volts and the memory to 2.2 volts with a 1:1 divider. Everything else was left on AUTO or default.

Windows reported 1.328 volts at idle which is pretty much equal to the Intel default of 1.325 volts. Pretty hard to complain about a 75% overclock with a minimal amount of effort and only needing default CPU voltage to get there.

What processor are you running on your DS3 and what sort of problems are you having with your board? They're not all bad.