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Basic OC maths and myths in one place: guesses by a noob

Last response: in Overclocking
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May 3, 2007 1:23:28 AM

I have heard the basics of overclocking are simple. But there are several numbers that seem to pop up in every explanation that are not explained. I will make a series of numbered statements and hope that somebody out ther knows the answer and can say true or false and explain a little. Or even add to these.

1.) Processor Bus speed times multiplier = processor clock speed.

2.) You can increase the the processor clock speed by either increasing the multiplier or by increasing the bus speed.

3.) Example of #2: 266Mhz bus times multiplier of 9 = 266Mhzx9 = 2394Mhz or 2.4Ghz (approx). Now increase bus to 288Mhz, leaving the multiplier at 9 and you get 288Mhzx9 = 2592 or 2.6Ghz (approx)

4.) Many motherboards now lock the multiplier because they can. So most people tell noobs like myself to just increase the bus speed

5.) Just increasing the bus speed affects the RAM and you WILL have to change the ram speed.

6.) You have to raise the RAM speed the same proportion you increase the bus speed

7.) Example of # 6. So if you had DDR2 533 ram and you increased your processor bus speed from 266 to 288 (an 8,27% increase) you would need to run your ram at 533x1.0827 = 577 Mhz

8.) The ratios 1:1 3:4 1:11 mean nothing and are just used to confuse us noobs. kind of like rm -rf while in root? Where did my files go anyway.

9.) Increasing the clock speeds are math and there is a specific answer if you want a specific result. Other things are more rules of thumb like voltage of the ram and voltage of the processor

10.) If a mobo says it can run DDR2 800 ram you can actually stick DDR2 1066 or faster ram in the mobo without overclocking and run it at DDR2 800 speed and use it's potential at a later time.

11.) I have no idea about ram timings 5-5-5-12??

12.) I have no idea about "The ratio" 1:1, 2:6...
May 3, 2007 12:11:38 PM

I think most of your assumptions are correct, based on what I've leaned on this site.

I think the RAM ratio is to keep the RAM frequency the same as the FSB speed increases.

I think RAM timings are the delays between each step in one clock cycle, but I'm not 100% on this.
May 3, 2007 1:18:53 PM

Quote:
Check out this link:

http://www.hardwaresecrets.com/article/26

The idea is that you lower the RAM speed so that when you increase the fsb the RAM will increase back up to its rated speed. Unless you also want to overclock the RAM.


Yep that's right, I had a ddr2 800mhz ram in my build and when i did some test over clocking I had to change the ratio, so I could move past 2.8 Ghz. The big thing I have questions on in the voltage to the different parts, I understand vCore, but not the others.
May 3, 2007 1:58:31 PM

what you have there is generally correct. but, for:

4.) It's the CPU makers that lock the multiplier not the motherboards so you have to buy the higher priced unlocked chip. This is why your only option to OC a cheap chip, is to OC your FSB.

5) yes on the bus speed, but some mobos let you unlink your RAM fsb from your system fsb and push your chip to high OC on standard mem.

6) not sure what you mean by proportion but there is a correlation. I have noticed on my mem that there is a formula for stability with RAM and system FSB. The board auto balances the two when unlinked but you can manually set it. Its most stable at 2X the system FSB a 450FSB, the RAM likes to run best at 900Mhz - unlinked, but it will run faster.

11) I don't think anyone really knows exact timings unless their a RAM engineer but usually the T settings of 1T or 2T are important as well as the lower your timings 4-4-4-12 , etc the faster your RAM will perform and boost your overall system speed. 1T 4-4-4-12 800Mhz is about as fast as 2T 5-5-5-12 1056Mhz, roughly
May 3, 2007 6:07:42 PM

So I kind of remember form my computer hardware class.
I think the timings stand for:
Read latency (measured in nano-seconds)
Write latency
Delete latency
Overwrite latency

Possibly not in that order.

The less time between successive writes reads etc. the more memory operations per second you can perform. However, if you do not give your memory enough time to perform a read/write/... operation there may be a signal that does not have enough time to get to the next gate in time and will cause an error such as data corruption.
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