D975XBX2 Overclocking

[tootall]

First, I have seen a lot of bad press related to this board and I just wanted to say that I really like it. I have had my share of issues with configuration and overclocking but by methodically working through them I am starting to get it to rock. To me this is part of the fun and I am learning all kinds of interesting things. Now on to overclocking. I would like some opinions. I have been reading a lot and have found the following link very helpful: http://www.peakin.com/xbx2/. I have determined that it is easy to overclock the fsb to increase the processor speed but much more difficult to get the memory overclocked to have the same "real world" throughput. This is because I have 800MHz memory. Is there really much advantage to overclocking the processor if you can not match that throughput with the memory? It seems to me that if these two are not close to matched then you are basically getting the overall throughput of the lower of the two. What is a realistic percentage to try and overclock the memory frequency by? I am not trying to do anything extreme, just curious on what percentage should be feasible.

[kenc51]

95% of the time, running the RAM in-sync with the CPU FSB gives the best performance.
Intel chips work best when the RAM is running @ 533MHz or 667MHz

The Intel FSB runs at 1066 or 1333MHz, but this is marketting speak. The real speed is 266 or 333MHz depending on the CPU.
If your RAM is running @ ~800MHz and the CPU is stock, then the FSB will be lower than the RAM speed. This causes a bottleneck and you don't see the performance.

You should set your RAM to run @ 533MHZ (if the fsb is 1066) and then increase the FSB to overclock. Since your RAM is rated for 800MHz you shouldn't have to worry about the ram crapping out and giving errors.

I'm sure someone can chime in here and explain it a bit better for you.

[Sparky]

This link has helped me set my XBX2 memory along with my OC.

http://www.peakin.com/xbx2/calculator.html

[tootall]

I agree that the calculator is an excellent tool. I am now at 360/266/533 running fine without changing any voltages. This is giving me around 11500MB/s fsb and memory per the calculator. I am now stress testing this set up for stability. I am happy with the 35% overclock on the fsb. It seems that when I overclock my memory even a small amount (842MHz vs 800MHz) it is not stable at all. MemTest82+ fails all over the place. I am not sure if it is because of the frequency overclock or my tightened timings (4-4-4-12 vs 5-5-5-16 (SPD nominal of 5-5-5-15)). I am going to make sure I am stable where I am at before proceeding any further. My goal is to try and get to 399/266/533 for around 12800MB/s throughput on both sides of the bridge. I do not think I can get there without raising voltages, but we shall see. Does anyone know how tightening the memory timings would affect the output of the calculator linked above? If I knew then what I know now I would have sprung for faster memory.

[Topol]

I've followed everything everyone is saying on this topic except 1 concept: the estimated real world throughput of the DDR2 RAM. In looking through the formulae used, he took 30% off of one of the two DDR's. Why? This one concept is the difference between sync'ing the RAM and the FSB at 533 (for this Intel board) and letting 800 RAM run natively.
Any thoughts?
BTW, here's what I've gotten to thus far:
2.24 GHz from a 1.86, E6300 (~20% overclock, according to the almighty calculator)
I only have an air-cooled system and am looking for stability more than velocity, so I think I'll stop about there for now (unless people think that 20% is bush league?)
Topol

[IRQ Conflict]

20% is a little weak. I'm running @ 50% OC @ 2.8Ghz 400/266/533 1:1 ratio @ 802Mhz ram.

My ram is the limiting factor in my OC. I'm sure the 6300 will go higher but my ram craps out if it goes to high. The only issue you may run into may be heat.

I'm running AS5 with a Scythe ninja and 2000RPM 120mm fan and I idle @ 37-41c (2.4Ghz) and load 58-61c (2.8Ghz). The TIM has not had time to cure yet though, so we will see.

[Topol]

What are your voltages set at? As this is my 1st time, I've been hesitant to play around with those too much. I can't get to the BIOS at the moment (downloading Windows security update), but the only voltage I have touched is the FSB voltage and that one I took it up 1 notch only. I assume to get maybe 35 - 40%, I'm going to have to really amp up the juice to the CPU, the FSB, and the memory?
Any tips you have on how you OC'ed you DIMMs would be appreciated as well. I've been focusing on getting a stable mobo first and then I am going to turn to tweaking the RAM this weekend.

Is it normal to have a split in core temps? They are only off by 1 degree at idle, but running a delta of 2 - 4 w/ a load. Should I be worried?

[IRQ Conflict]

All @ stock voltages. It's normal for the two cores to be at a slightly different temp.

Depending on your ram and how much faster you want to go with it you may need to increase that.

I would start at the highest voltage allowed without voiding the rams warranty, then see how fast you can get the ram to be stable at 24/7.

Unless your into extreme OC'ing I would try to remain conservative. And invest in better cooling.