Gadgetory

twenty-two core Intel Xeon Broadwell ie five chips pack over seven billion transistors the number of people here on earth into a space no larger than a quarter like why is the GTX ten eighty from Nvidia Spassky lineup packs the same number into the size of a penny but with all of these microscopic or nanoscopic transistors squeezed into such small areas there's bound to be a bit of heat involved in fact some of these CPUs and GPUs require unique forms of cooling to keep cool even while maintaining subpar clock speeds but why what exactly about CPUs and GPUs makes them run so hot there's actually more than one answer to that question welcome to crash course first let's discuss what exactly a transistor is picture them like light switches they're designed to either allow or prevent electricity from flowing through a circuit via the use of a semiconductor thus they have conductive States and insulating states and special signals to inform the transistors of when to act like one or the other there are entire classes devoted to just transistor theory I plenty of friends who have already made it through the curriculum and they would probably tell me that this is a very gross oversimplification but this is all we need to know for what we're about to discuss next so inside processors billions of these transistors are constantly switching quote-unquote on and off to control electron flow through various gates they're also switching it rates much faster than overall CPU and GPU clock speeds although these frequencies are indirectly relative now if you've ever taken a class in thermodynamics or just studied mechanical properties in general you know that the second law of thermodynamics is just that a law everything in the universe has energy and perfect energy conversions and transfers are impossible so when electricity flows through in the case of a CPU primarily aluminum copper reacts with other components within the silicon so it's not generally used the resistive properties of the aluminum yield energy loss in the form of heat which is why any aluminum wire heats up when electricity flows through it so to be exact pure aluminum has resistance of 2.6 5 times 10 to the negative 8 ohms times the quotient of wire length and cross-sectional area however since processors are generally small and electrical pathways are literally microscopic this is not responsible for most of the heat produced within the die as it would be logical to assume then that the number of transistors within the die is directly proportional to the amount of heat produced right no in fact sometimes the exact opposite is true consider two processors the i7 4790k from Intel and its 6700 K counterpart both processors contain the same number of cores and threads but not the same number of transistors yet still both processors have relatively identical TDP s that is the maximum amount of heat a CPU can generate or GPU can generate that must be dissipated by a cooling system this is thanks to several factors one being the thermal design of the chip itself where blocks are situated within the die and also how small the transistors themselves are even though there are more of them in the 6700 K each dissipate less heat smaller form factor lower resistance lower thermal design on a sidenote individual transistors smaller than roughly 5 nanometers about a third of the size of what we're currently running would experience a unique effect the spaces electrons must travel through at around the size become so small that the only way they can pass successfully through a semiconductor is via quantum tunneling this is a separate quantum mechanical phenomena that involves the borrowing of energy at the subatomic level from the electrons surroundings but more on that in another crash course so transistor alternation size clustering and power distribution all play a role in processor heat generation and so too does clock speed every computer enthusiast knows that overclocking a CPU or GPU always always results in a higher thermal output and here's the catch voltage doesn't have to change on paper this really doesn't make sense if voltage ultimately drives resistance we're talking Ohm's law here and resistance is converted to heat then a voltage change of zero should yield a thermal design change of zero but thanks to how transistors work clock speed directly affects TDP here we go as transistors switch from an active state to a passive state and back again to an active one they release Heat thanks to partial resistance remember so as clock speed increases so too does the alternation rate it isn't directly proportional the frequency of 4k Kurtz doesn't mean that your transistors are alternating at four billion times a second it actually means they're alternating at higher rates than that and if you overclock all cores and your chip equally which you'll have no choice but to do when it comes to GPUs most of them have some thousand course thermal output increases at a rather obtuse exponential rate this means that for every factor one of overclock let's say 100 megahertz heat is generated at a factor greater than 1 this value varies from chip to chip but it explains why past a certain frequency chips become very stubborn and get very very hot regardless of voltage input you're essentially asking transistors within your processor to alternated rates much higher than they were thermally designed for so if you wish to venture any higher than that threshold typically around 5 gigahertz or so special cooling systems are required and remember this is all thanks to the second law of thermodynamics no system is perfect everything loses energy in the form of heat your own body does our Sun does the earth does in fact the entropy of the entire universe is increasing and from the vastness of galaxies down to the very transistors powering your computers and phones you're using to watch this video at this very moment everything is currently giving off heat traveling from states of higher energy to lower energy except in the case of endothermic reactions again another video but you my friends are still very cool now we've discussed quite a bit in this video after all it is a crash course so if there's anything you need a refresher on refer to the description of this video you'll find a table of contents and the timestamps will take you exactly where you need to go if a quick refresher is in order and there's nothing wrong with that I know I speak very fast but that's just how it's gonna be here on the channel speaking of which if you like this channel and like what you saw in this particular video be sure to give this thing a thumbs up give it a thumbs down if you feel the great option or if you hate everything about life be sure to click the subscribe button you have everything stay tuned for a future PC build and more crash course content because I just like doing different things every day and coming up with new topics and taking advice from you guys and doing stuff that you want to see be sure to follow me on Twitter if you haven't already at sc/st Salizar give me the inside scoop of what's going down what you're confused about and be sure to address those issues maybe on a show like this stay tuned for the next one folks this is science studio thanks for learning with us