Core i9 Overclocking Guide – You asked for it!
Linus Tech Tips
·Linus Tech Tips
·2018-05-06
·
1,630 words · ~8 min read
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ever since our core i9 review we've been planning to do an x299 overclocking
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guide but at that time the whole lineup hadn't even been launched yet so
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fast forward to today we finally got our
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18 core chips and get this
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Intel wanted to sponsor an overclocking guide so we were like
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heck yeah let's do it
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okay so if you're in a hurry to squeeze a little more performance out of your
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system you could just run ASUS's easy
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tuning wizard or the equivalent from your motherboard manufacturer
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but you're here watching so my guess is you
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want more so then first order of business is
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component selection you're going to want to choose a motherboard that can handle
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the juice that your high core count CPU
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will need pick one with two eps 12 volt
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connectors to spread the current out over more wires like the ASUS prime x299
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deluxe or even a rampage series board
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and a high quality power delivery system
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with good cooling without robust vrms and adequate
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ventilation you should not attempt x299
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overclocking and this is especially true for the power hungry extreme edition
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which brings us to the next item on our shopping list the power supply you won't
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need to harness the power of the atom
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but core i9 htc chips alone can pull as much
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power as an entire mainstream gaming
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system when overclocked up to 500 watts
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off the 12 volt rail so most 850 watt 80
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plus gold and higher units will do you nicely but
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double check with a power supply calculator for your setup and the
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continuous load table before you buy i
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would actually even start at a thousand rather than 850 watts for a 14 core or
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higher next up then is cooling you'll want a
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lot of it from our review the core i9 series gets
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pretty toasty under load even at stock speed so whether you choose to get
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adventurous and replace the thermal compound under the heat spreader via the
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method that we showed off here or decide to keep your warranty more
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intact we recommend at least a 280
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millimeter aio like the Corsair h115i or
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a large air cooler like Noctua's nhd15
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and for the first time in years actually a
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custom water cooling loop is actually highly recommended for the best results
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as for the rest of the components higher spec RAM wouldn't be a terrible idea but
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it should be noted that in most cases it doesn't affect performance too much
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beyond 3000 megahertz and the rest pretty much comes down to personal taste
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and the goal of your build your SSD or your graphics card won't
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affect your ability to overclock
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unless they get lodged in your cooling fan
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okay then so you've got your build put together and a fresh install of the os
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of your choice time to get down to business
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we still prefer using the BIOS over tools
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like Intel's surprisingly versatile extreme tuning utility in Windows
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because we're old school like that so first off xmp
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if you spent a few bucks on fancy RAM you'll probably want this on but if you
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run into stability issues turn it off then let us know in the
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comments if you'd like a separate video down the line discussing tuning RAM
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frequency and timings manually next whether xmp is off or on you'll
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need to disable CPU s-vid support and
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speed step which prevents the CPU from communicating with the external voltage
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regulator and from down clocking to save power while idle
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once you've finished with that find where your UEFI BIOS keeps its power
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control options listed on our ASUS board as external
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digiplus power control we are interested in a few items in here for load line
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calibration start out with a lower value like two or three this provides extra
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voltage so that as the CPU goes from zero to 100 when you fire up a demanding
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load it doesn't wind up starved for power momentarily causing an error
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it should be noted though that this setting can exacerbate the thermal issue
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there is a reason why it's off by default
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CPU current capability should then be set to 140 percent which will allow more
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power to be supplied to the CPU this prevents a difficult to diagnose
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condition known as vrm throttling then
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spread spectrum should be disabled for stability and CPU power phase control
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should be set first to extreme and then
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dial back if possible once you've found a stable clock speed that you like
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your final stop sort of overclocking can be a bit of a
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rabbit hole is CPU core ratio
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which we recommend changing to buy specific core which allows you to
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specify ratios and voltages for each
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individual core along with an asterisk
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here that denotes the higher tolerance turbo boost max cores
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so 4.2 gigahertz is the non-max single
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core turbo speed for the 7900x so we'll
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use this as a starting point tweak the multiplier higher rebooting in
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between each step until you reach an unstable level where the system won't
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boot then you've got a couple of choices you
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can either bump the voltage up and see if you get stability we chatted with our
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friends over at gamer's nexus they figure about 1.25 volts on decent water
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cooling is about as high as you want to go or
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you can drop back to the last stable setting or to be safe one increment
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lower and try it again now those asterisk cores those can clock
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higher with lower voltage so be sure to take this into consideration while
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you're tuning the more you can control the heat output of your chip the better
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your results and the lower the voltage the less heat
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speaking of you may actually not need or want to add much voltage if
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you can help it unless you've got a custom loop in some cases like our ASUS
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board using offsets will actually offset
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from the auto voltage meaning that you might even want to push them negative
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depending on the readings that you get remember guys even small incremental
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bumps and voltage count for a lot when we're talking about up to 18 cores
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though this can be alleviated somewhat by using
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what's called an avx offset which down clocks the CPU by a set amount when
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running complex avx enabled workloads so
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ASUS BIOS shows the avx frequencies separately so you can actually see the
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offset's results alright then
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so if all goes well you've got some settings dialed in that will work for
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your CPU here's what we're using
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if not clear the cmos and try again until you
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do now it's time for burn-in testing now
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the traditional wisdom says to run a full system load like prime95 for 24
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hours to validate your overclock make sure your CPU is not going to spit out
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any calculations that aren't correct but while that's a good idea and we would
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still recommend it we've seen a lot of situations where even a 24-hour pass
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doesn't mean it's fully stable the real test for us lately has been in
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heavy start stop loads we've actually caught more stability failures using the
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3d modeling software blender which hits the CPU hard across all cores
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so there are free scenes that can be used to benchmark and passing longer
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ones like the classroom barcelona pavilion or the gooseberry production
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benchmark tends to be the final pass for us
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now if you're working on this and you feel like you're close but you're not
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quite stable you can maybe try increasing your CPU input voltage
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starting at about 450 millivolts above your core voltages
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it can help you can also try boosting the system agent voltage and bringing
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vccio up to within 50 millivolts of it to account for variants in CPU memory
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controllers especially if you're using xmp or overclocking your RAM
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once everything's stable and you're comfortable with your thermals which you can monitor using a free tool like
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hardware info 64 you've got a few options
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you can increase the clocks and rinse and repeat go through this whole process
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again you can just stick with what you have or
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for the adventurous you can actually start trying to reduce CPU core voltages
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re-enable power saving features and reduce voltages for the encore pll and
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vccio to help tame the heat output
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then validate it all over again it is a long process if you really want
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to get it dialed in perfectly but once you've done so you'll be left with
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a nice performance bump over the stock configuration
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in our case we managed some good gains in clock hungry gaming and our already
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good productivity performances unsurprisingly even better which means
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you can get your work done faster and get back to pwning noobs
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all without ever leaving the comfort of the glow of your battle station
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so thanks for watching guys if you disliked this video you can hit that button but if you liked it hit like get
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