Author: Aaron Gordon
Date: 14:51:47 07/02/03
Go up one level in this thread
On July 02, 2003 at 11:24:12, Vincent Diepeveen wrote: >>Since the cores are all technically 2.4GHz, running one of these cores (from the >>hand-picked XP 1700+ chips) at 2.0-2.4GHz isn't overclocking at all. This is >>similar to taking a P4-3.06 remarked to 2.4GHz, then modifying it back into a >>3.06.. is that overclocking? No. > >It is overclocking by definition. A product you bought to be running X you run >at y > x. > >It even more emphasis to the average user to not overclock himself. >Overclocking is a dangerous business. > >A big problem of overclocking is that the reliability becomes less of for >example the FPU. Now you might care shit for this, because you only 'test' it >for a few seconds, but the reason those cores are clocked for example at 2.2Ghz >where you find out that they 'work' for you at 2.4ghz is because some parts at >the cpu are not handling 2.4Ghz very well. Only test it for a few seconds? Read my webpage AND previous post. I test for 24 hours on single CPU chips and 48 hours on dual capable chips. >A good example is the itanium2 cpu's 0.18 which were clocks 900 and 1 Ghz. Intel >has either all ordered them back to factory or clocked them back to 800Mhz, >because they found out that in some calculations users lost bits. > >It is exactly this that will happen at your chips. Just because you can program and babble on about matrix garbage doesn't mean you know a single thing about overclocking. The chips *ARE* stable. Not a single one has had a problem after I've shipped it to a customer. The methods and equipment I use ensure full stability under and situation. As I mentioned previously I have a 'cushion' of MHz. I clock the chip back a bit after ensuring stability. When overclocking the chip will go from completely stable to extremely unstable over a small temperature range when you're on the 'edge' of stability. I let it get very warm (55C+) then find the chips 'edge'. I then back the MHz up just a little and test until its completely stable. After this I knock the chips MHz back a significant ammount, ensuring complete stability. Intel increases voltages (from 1.50v to 1.525 & 1.55v) to help increase yields. This helps the chips run higher, and if you wanted to get down to the engineering level you could consider that a mild form of overclocking. Taking lower yield chips, boosting the voltage and selling them faster. Intel has been keeping the chips right on the edge at times (not all of the time of course).. this is why they had to recall the P4-3GHz C, Itaniums and P3-1.13GHz. They know what the cores are doing (guesstimate) then sell the chips slightly lower. Sometimes they guess wrong & end up with an unstable chip. If they tested the chips before hand like I do, they wouldn't have this problem. Of course there is absolutely no time for AMD/Intel to run extended stability tests on every cpu they produce. It would cost too much money and take a massive ammount of time. I go the extra mile by testing the chips more than Intel/AMD would ever hope to test their chips, then I do as I stated in the previous paragraphs. You don't know the minute effects of voltage changes on a chip in reguards to overclocking & heat, I do. If you need me to show you some proof mathematically, I can do that as well. When trying to find calculations on a cpu you never, ever calculate by the chips "rated" speed, the core is almost always much better. Take the latest hand-picked 1700+ (1.46GHz) chips. Lets say after 24-48 hours of testing we find the core can do 2440MHz at 1.75v, completely stable via Prime95/BurnK7 for hours and hours at 60C (via Standard heatsink and fan running low rpms, to raise cpu temp to 60C intentionally). Todays chips will do exactly 100% more at their absolute maximum if you drop the temperature 160C. Thus a 1.47ghz rated chip with a 2.5GHz core (40C maximum stable temp for example) can run 5.0GHz at -120C. Using this constant, 0.625 (or 160/100), you can figure out the following. Lets take our example cpu from before, (max 2440/1.75v @ 60C), we can do this: We know the normal user won't run 60C, with average cooling (0.16 c/w heatsink) and figure in an ambient case temp of 30C, and the cpu at 2440/1.75v being 86.509 watts. You can figure out the chips wattage by doing, Overclocked Watts = Default Watts * (Overclocked Mhz \ Default Mhz) * (Overclocked Vcore \ Default Vcore)² I used the numbers from an Athlon XP 2700+ (2167MHz, 68.3 watts, 1.65v) and scaled it to 2440MHz, 1.75v. So, the wattage is accurate. Now, back to cooling. You can figure out the CPU temperature by doing this: cpu temp(celsius) = (wattage * c/w) + ambient (celsius) 43.84144 = (86.509 * 0.16) + 30 So, 43.84144C cpu temp with a 0.16c/w heatsink/fan (this is 0.16 degrees celsius increase per watt). Using the constant of 160 per doubling, we can now figure out that max cpu speed (with the same stability as 2440/1.75v/60C) at 43.84144C. We do: 2686.41804MHz = 2440 * ((((60-43.84144)*0.625) / 100) + 1) So, at about 43.85C it's capable of running 2686MHz, and that is the SAME stability as 2440/1.75v/60C. Now, upping the voltage to 1.85v also helps stablity. Lets first calculate the slight MHz drop from the temp increase at 1.85v. If 2440/1.75v == 86.509 watts, 2440/1.85v == 96.678 watts (still cooler than a 3GHz P4!). This will result in a cpu temperature of 45.46848C and a new max stable speed of 2661.60568MHz. Now, to figure out the speed increase from upping the voltage from 1.75v to 1.85v, we do a simple linear equation: 2813.70~ = 2661.60568 * (1.85 / 1.75) End result, our "example" CPU is capable of doing ~2.8GHz questionably stable and is clocked down to 2.4GHz. The CPU will be completely stable beyond any doubts. This is what I do, the chips run perfect. Please take your asinine babble elsewhere, Vincent. >So for those people who sometimes run crucial software, they cannot use your >chips at all. > >That i personally am busy with computerchess and that everything is an >approximation there and all is integers and not floating point, makes me simply >an exception. > >Despite that i didn't do effort to clock my 2.1Ghz chips to 2.2Ghz. > >Best regards, >Vincent
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