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Studying to OC. Question. - Page 2

post #11 of 18
..anymore..still got a few.
post #12 of 18
Thread Starter 
Umm... I have many questions about "Combining Memory and CPU Overclock: Looking for Long Term Stability", but I can't think of just one right now. It's still a bit hard to understand what he is doing in the guide, until I read more.

I'll have alot more questions posted tonight in one continously edited post. So check back tomorrow and join the fun
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post #13 of 18
or PM me if its off topic.
post #14 of 18
Thread Starter 
I'm having trouble understanding this page and what he is doing. I know he is combining memory and CPU overclocks together hoping to get a stable system, but I keep reading and I don't understand his charts.

I wish I could explain what I don't understand better.

F*** this get's frustrating. I'm going to bed, I'll trample through this more tomorrow.
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post #15 of 18
Quote:
a weak IMC may begin exhibiting problems at higher CPU clocks, even though it appeared fine in the previous section. A 300MHz memory clock may be perfectly fine at 2.1GHz, but at 2.6GHz, the behaviour may be different altogether.
The article is touching on the IMC [integrated memory controller] inside the CPU. For a stable system and a good OC, you need to test each successful OC using a few benchmarks. Due to all of the variables, FSB, CPU speed, RAM speed, IMC speed and HTT link speed...it can get very touchy trying to maximize all of those things together.

It then goes on to say..
Quote:
I immediately recognized that 10x261 was perfect for the BH-5, as it had no issues pumping out 261MHz at 2-2-2-5 timings, and this is very close to it's maximum clock speed at the voltages I tested with. If this proves to be stable, we are literally getting the best of both worlds.

In a perfect world where every chip has a perfect IMC, 9x290 would have been a great choice for my TCCD. Unfortunately, 290MHz is not going to happen with my Winchester and 1GB of RAM, so I will likely have to use 11x238MHz and take advantage of the tighter 2-3-3-6 timings it is capable of at that speed. I could also use 10x261MHz for the TCCD but it only proved stable with rather loose 2.5-4-4-8 timings. 11x238MHz at 2-3-3-6 timings is still a better choice. Hopefully this will prove to be stable with a 2.6GHz CPU clock.
Faster RAM is always good...but not at the cost of too much latency from loose timings. So, 'he' is determining the fastest RAM clock speed, according to the maximum CPU clock he can run. Since ~260mhz is close to the max speed for his RAM..he is choosing a 1:1 ratio to keep the highest CPU clock and the highest RAM speed. If his RAM was capable of a little more speed..he couls easily run the 5/6 divider, to still have a 2.6ghz cpu...but with his RAM only at ~231mhz...he would still have some room to OC his CPU, more, before the RAM reached its limit of ~260mhz again.
-----------------------

The point is to find the best combination for your OC..(highest CPU speed + lowest timings/fastest speed, for your RAM) If stability becomes and issue, you can adjust your CPU multi, to change the dividers/speed ratio, or lower your HTT freq.

to calculate your divider, take the FSB base clock, if at 250mhz FSB using a 3/4 divider.. you do the foolowing :

(250 * 3) / 4 = RAM speed of 333mhz...or ddr 667 <-maxxed out RAM speed
(250 * 4) / 5 = RAM speed of 312mhz...or ddr 624 <- RAM still too fast!
(250 * 5) / 6 = RAM speed of 208mhz...or ddr 416 <- Good divider!!

...are you understanding somewhat now?
post #16 of 18
    
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post #17 of 18
Thread Starter 
Quote:
Originally Posted by CL3P20 View Post
...are you understanding somewhat now?
I understand a little better than I did. I'm still confused though. I'll try to explain my understanding, correct me if I'm wrong.

When he's finding the balance of cpu memory, he uses 2618MHz as his best clock and I understand why. He's using 11x238=2618MHz, then he uses these numbers,
1/1 - 238MHz
5/6 - 187MHz
2/3 - 154MHz

I get where the numbers came from, 1:1, 5/6, and 2/3 are memory dividers, aiming for 1:1 if possible. He tries to pick a divider that gives him a memory frequency that was stable when he was trying to find his max mem. freq. right? He is going to use 11x238 with 238(1:1) memory freq., but I dont see a successful 238 mem freq with 2-3-3-6 timings on the previous page. I see a successful 238 with 3-3-3-8 timings.

I understand how he is finding max cpu/memory parts but I don't know where he is getting some of his numbers and selecting them on the balance of cpu memory page.

Does OCN have an IRC or ventrilo/teamspeak?
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post #18 of 18
The numbers listed are just the values of the FSB/RAM ratio's. Just as too high of a divider can increase RAM speed to the breaking point, a divider thats too low, could slack on the RAM speed, yet push the CPU speed too far.

If you have some good RAM...then try a 1:1 to see how far you can take your CPU and RAM together...if you are getting an unstable system, try a different divider, for a slower CPU/faster RAM combo.. It's really just getting to 'know' your hardware and its limitations. You have got to know the limits of your RAM, to be able to push your CPU to its limits..and vice versa, especially if you are trying to achieve the fastest speed for your Mobo/CPU/RAM all together. Some folks could care less about running their RAM at 900mhz vs 800mhz...so they simply clock their cpu to a point where they can use the next lowest divider, to run their cpu at a higher speed and still run stock speed on the RAM.

Only the tests you do, will show you what you will be better suited to run your rig at...then personal preference, experience and 'oc flavor' make up the rest.
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